diff --git a/app/Http/Controllers/Care/SettingsController.php b/app/Http/Controllers/Care/SettingsController.php
index c61c02e..5de75b2 100644
--- a/app/Http/Controllers/Care/SettingsController.php
+++ b/app/Http/Controllers/Care/SettingsController.php
@@ -79,7 +79,7 @@ class SettingsController extends Controller
         ]);
     }
 
-    public function update(Request $request, QueueClient $queue, CareQueueProvisioner $provisioner): RedirectResponse
+    public function update(Request $request, QueueClient $queue): RedirectResponse
     {
         $this->authorizeAbility($request, 'settings.manage');
         $organization = $this->organization($request);
@@ -136,6 +136,8 @@ class SettingsController extends Controller
             $wantsQueue = false;
         }
         $settings['queue_integration_enabled'] = $wantsQueue;
+        $queueWasEnabled = (bool) data_get($organization->settings, 'queue_integration_enabled');
+        $queueJustEnabled = $wantsQueue && ! $queueWasEnabled;
 
         $settings[AppointmentPatientNotifier::SETTING_BOOKED_SMS] = $request->boolean('notify_appointment_booked_sms');
         $settings[AppointmentPatientNotifier::SETTING_BOOKED_EMAIL] = $request->boolean('notify_appointment_booked_email');
@@ -184,27 +186,49 @@ class SettingsController extends Controller
             }
         }
 
+        // Queue department sync + waiting-ticket backfill can take minutes over HTTP.
+        // Never block the settings response on it — run after the redirect goes out.
         if ($wantsQueue && $queue->configured()) {
-            try {
-                $organization = $organization->fresh();
-                $provisioner->provisionOrganization($organization);
-                // Backfill tickets for patients already waiting when Queue was just linked.
-                $bridge = app(CareQueueBridge::class);
-                $branches = Branch::owned($owner)
-                    ->where('organization_id', $organization->id)
-                    ->where('is_active', true)
-                    ->pluck('id');
-                foreach ($branches as $branchId) {
-                    foreach (array_keys(CareQueueContexts::departments()) as $context) {
-                        if ($context === CareQueueContexts::RECEPTION) {
-                            continue;
-                        }
-                        $bridge->syncMissingTickets($organization, $context, (int) $branchId, 50);
-                    }
+            $organizationId = (int) $organization->id;
+            $backfillTickets = $queueJustEnabled;
+            dispatch(function () use ($organizationId, $owner, $backfillTickets) {
+                $organization = Organization::query()->find($organizationId);
+                if (! $organization) {
+                    return;
                 }
-            } catch (\Throwable) {
-                // Best-effort; role pages will lazy-ensure on next use.
-            }
+
+                try {
+                    app(CareQueueProvisioner::class)->provisionOrganization($organization);
+                } catch (\Throwable) {
+                    return;
+                }
+
+                if (! $backfillTickets) {
+                    return;
+                }
+
+                try {
+                    $bridge = app(CareQueueBridge::class);
+                    $branches = Branch::owned($owner)
+                        ->where('organization_id', $organization->id)
+                        ->where('is_active', true)
+                        ->pluck('id');
+                    foreach ($branches as $branchId) {
+                        foreach (array_keys(CareQueueContexts::departments()) as $context) {
+                            if ($context === CareQueueContexts::RECEPTION) {
+                                continue;
+                            }
+                            try {
+                                $bridge->syncMissingTickets($organization, $context, (int) $branchId, 25);
+                            } catch (\Throwable) {
+                                // Continue other contexts/branches.
+                            }
+                        }
+                    }
+                } catch (\Throwable) {
+                    // Best-effort; role pages will lazy-ensure on next use.
+                }
+            })->afterResponse();
         }
 
         AuditLogger::record($owner, 'organization.updated', $organization->id, $owner, Organization::class, $organization->id);
diff --git a/app/Services/Care/DemoTenantSeeder.php b/app/Services/Care/DemoTenantSeeder.php
index a57fbe2..d363674 100644
--- a/app/Services/Care/DemoTenantSeeder.php
+++ b/app/Services/Care/DemoTenantSeeder.php
@@ -97,75 +97,75 @@ class DemoTenantSeeder
         $this->ensureOnboardedShell($user, $plan);
 
         if ($reset) {
-            DB::transaction(fn () => $this->resetTenant($ownerRef));
+            $this->resetTenant($ownerRef);
             $this->ensureOnboardedShell($user, $plan);
         }
 
-        return DB::transaction(function () use ($user, $ownerRef, $plan, $volumes) {
-            $organization = $this->upsertOrganization($user, $ownerRef, $plan, $volumes['branches']);
-            $this->upsertOwnerMember($organization, $ownerRef);
+        // No outer transaction — Enterprise volumes can hold row locks for minutes
+        // and 500 concurrent settings/login requests (messaging credentials, org updates).
+        $organization = $this->upsertOrganization($user, $ownerRef, $plan, $volumes['branches']);
+        $this->upsertOwnerMember($organization, $ownerRef);
 
-            $branches = $this->seedBranches($organization, $ownerRef, $volumes);
-            $this->seedStaffMembers($organization, $ownerRef, $plan, $branches);
-            $departments = $this->seedDepartments($branches, $ownerRef, $volumes);
-            if (in_array($plan, ['pro', 'enterprise'], true)) {
-                $this->seedSpecialtyModules($organization, $ownerRef);
-                $departments = $this->departmentsByBranch($branches, $ownerRef);
-            }
-            $practitioners = $this->seedPractitioners($organization, $branches, $departments, $ownerRef, $volumes);
-            $patients = $this->seedPatients($organization, $branches, $ownerRef, $volumes);
-            $appointmentCount = $this->seedAppointmentsAndClinical(
+        $branches = $this->seedBranches($organization, $ownerRef, $volumes);
+        $this->seedStaffMembers($organization, $ownerRef, $plan, $branches);
+        $departments = $this->seedDepartments($branches, $ownerRef, $volumes);
+        if (in_array($plan, ['pro', 'enterprise'], true)) {
+            $this->seedSpecialtyModules($organization, $ownerRef);
+            $departments = $this->departmentsByBranch($branches, $ownerRef);
+        }
+        $practitioners = $this->seedPractitioners($organization, $branches, $departments, $ownerRef, $volumes);
+        $patients = $this->seedPatients($organization, $branches, $ownerRef, $volumes);
+        $appointmentCount = $this->seedAppointmentsAndClinical(
+            $organization,
+            $branches,
+            $departments,
+            $practitioners,
+            $patients,
+            $ownerRef,
+            $volumes,
+        );
+        if (in_array($plan, ['pro', 'enterprise'], true)) {
+            $appointmentCount += $this->seedSpecialtyDemoData(
+                $organization->fresh(),
+                $branches,
+                $practitioners,
+                $patients,
+                $ownerRef,
+            );
+        }
+
+        if ($volumes['paid_modules']) {
+            $this->seedPaidModules(
                 $organization,
                 $branches,
-                $departments,
                 $practitioners,
                 $patients,
                 $ownerRef,
                 $volumes,
             );
-            if (in_array($plan, ['pro', 'enterprise'], true)) {
-                $appointmentCount += $this->seedSpecialtyDemoData(
-                    $organization->fresh(),
-                    $branches,
-                    $practitioners,
-                    $patients,
-                    $ownerRef,
-                );
-            }
+            $this->seedDevices($organization, $branches, $ownerRef);
+        }
 
-            if ($volumes['paid_modules']) {
-                $this->seedPaidModules(
-                    $organization,
-                    $branches,
-                    $practitioners,
-                    $patients,
-                    $ownerRef,
-                    $volumes,
-                );
-                $this->seedDevices($organization, $branches, $ownerRef);
-            }
+        if ($volumes['assessments'] > 0) {
+            $this->seedAssessments(
+                $organization,
+                $branches,
+                $practitioners,
+                $patients,
+                $ownerRef,
+                $volumes['assessments'],
+            );
+        }
 
-            if ($volumes['assessments'] > 0) {
-                $this->seedAssessments(
-                    $organization,
-                    $branches,
-                    $practitioners,
-                    $patients,
-                    $ownerRef,
-                    $volumes['assessments'],
-                );
-            }
+        $this->syncQueueTicketsForDemo($organization->fresh(), $branches);
 
-            $this->syncQueueTicketsForDemo($organization->fresh(), $branches);
-
-            return [
-                'organization' => $organization->fresh(),
-                'branches' => count($branches),
-                'patients' => count($patients),
-                'appointments' => $appointmentCount,
-                'plan' => $plan,
-            ];
-        });
+        return [
+            'organization' => $organization->fresh(),
+            'branches' => count($branches),
+            'patients' => count($patients),
+            'appointments' => $appointmentCount,
+            'plan' => $plan,
+        ];
     }
 
     /**
diff --git a/app/Services/Messaging/MessagingCredentialsService.php b/app/Services/Messaging/MessagingCredentialsService.php
index 0685e92..d746794 100644
--- a/app/Services/Messaging/MessagingCredentialsService.php
+++ b/app/Services/Messaging/MessagingCredentialsService.php
@@ -14,10 +14,30 @@ class MessagingCredentialsService
 
     public function forOrganization(Organization $organization): MessagingCredential
     {
-        return MessagingCredential::query()->firstOrCreate(
-            ['organization_id' => $organization->id],
-            ['owner_ref' => $organization->owner_ref],
-        );
+        $existing = MessagingCredential::query()
+            ->where('organization_id', $organization->id)
+            ->first();
+        if ($existing) {
+            return $existing;
+        }
+
+        try {
+            return MessagingCredential::query()->create([
+                'organization_id' => $organization->id,
+                'owner_ref' => $organization->owner_ref,
+            ]);
+        } catch (\Throwable $e) {
+            // Concurrent create (or a long demo-seed transaction holding a lock)
+            // — prefer returning the row another request just wrote over 500ing.
+            $existing = MessagingCredential::query()
+                ->where('organization_id', $organization->id)
+                ->first();
+            if ($existing) {
+                return $existing;
+            }
+
+            throw $e;
+        }
     }
 
     /**