diff --git a/atlas/templates/atlas/collection_case_view_take.html b/atlas/templates/atlas/collection_case_view_take.html
index 53fc0023..5cf98fed 100644
--- a/atlas/templates/atlas/collection_case_view_take.html
+++ b/atlas/templates/atlas/collection_case_view_take.html
@@ -25,6 +25,7 @@
                     <div id="question-timer-progress-inner" style="width:100%; height:100%; background:var(--timer-color, #28a745);"></div>
                 </div>
             </div>
+            <div id="timer-htmx-target" style="display:none;"></div>
         </div>
     {% endif %}
 
@@ -414,15 +415,35 @@
                         var $next = $form.find('button[name="next"]');
                         var $finish = $form.find('button[name="finish"]');
 
-                        if ($next.length) {
-                            $next.prop('disabled', false);
-                            $next.click();
-                        } else if ($finish.length) {
-                            $finish.prop('disabled', false);
-                            $finish.click();
-                        } else {
-                            $form.submit();
-                        }
+                        // Instead of navigating away, submit via fetch with timed_out flag
+                        // Use HTMX to POST the timed_out flag and then lock the UI
+                        var onAfter = function (evt) {
+                            try {
+                                // lock the form UI in-place
+                                $form.find('input, textarea, select, button').prop('disabled', true);
+                                $form.addClass('timed-out-locked');
+                                $('#question-timer').text('Locked');
+
+                                // hide the progress bar
+                                $('#question-timer-progress, #question-timer-progress-outer, #question-timer-progress-inner').hide();
+                                // ensure inner shows empty state if something relies on it
+                                $('#question-timer-progress-inner').css({ width: '0%', background: '#dc3545' });
+                            } catch (e) {
+                                console.error('Error locking UI after htmx request', e);
+                            } finally {
+                                htmx.off('htmx:afterRequest', onAfter);
+                            }
+                        };
+
+                        htmx.on('htmx:afterRequest', onAfter);
+                        htmx.ajax('POST', window.location.href, {
+                            values: { timed_out: '1' },
+                            swap: 'none',
+                            headers: {
+                                'X-CSRFToken': document.querySelector('input[name="csrfmiddlewaretoken"]').value,
+                            },
+                            target: "#timer-htmx-target",
+                        });
                     } else {
                         $timer.text(formatTime(remaining));
                         updateProgress();
diff --git a/atlas/views.py b/atlas/views.py
index 136f0fc5..5c8af6b8 100755
--- a/atlas/views.py
+++ b/atlas/views.py
@@ -2786,11 +2786,33 @@ def collection_case_view_take(
                                 raise Http404("Self review not enabled")
                             answer.completed = True
 
+                        # If this was a timed-out submission, mark as completed
+                        if request.POST.get('timed_out') == '1':
+                            answer.completed = True
+
                         answer.save()
 
                         cid_user_exam.end_time = timezone.now()
                         cid_user_exam.save()
 
+                        # If this was an AJAX/HTMX request, return JSON so the client
+                        # can remain on the same page and update the UI without redirect.
+                        # Detect HTMX/XHR requests robustly. HTMX sets the HX-Request header.
+                        is_ajax = (
+                            request.headers.get('HX-Request', '').lower() == 'true'
+                            or request.headers.get('x-requested-with') == 'XMLHttpRequest'
+                            or getattr(request, 'htmx', False)
+                        )
+                        if is_ajax:
+                            from django.http import JsonResponse
+                            return JsonResponse(
+                                {
+                                    'status': 'ok',
+                                    'locked': answer.completed,
+                                    'submitted_at': answer.submitted_at.isoformat() if getattr(answer, 'submitted_at', None) else None,
+                                }
+                            )
+
         if cid is not None:
             kwargs = {"pk": pk, "cid": cid, "passcode": passcode}
             redirect_url = "atlas:collection_case_view_take"