diff --git a/collects/mred/exit.ss b/collects/mred/exit.ss
index c6ba2f53..e7cc5684 100644
--- a/collects/mred/exit.ss
+++ b/collects/mred/exit.ss
@@ -33,23 +33,28 @@
 		 [else (loop (cdr cb-list))])))))
 
     (define -exit
-      (lambda ()
-	(let/ec k
-	  (when (and (mred:preferences:get-preference 'mred:verify-exit)
-		     (not (let ([w (if (eq? wx:platform 'macintosh)
-				       "quit"
-				       "exit")]
-				[capW (if (eq? wx:platform 'macintosh)
-					  "Quit"
-					  "Exit")])
-			    (mred:gui-utils:get-choice
-			     (string-append "Are you sure you want to " w "?")
-			     capW "Cancel"))))
-		     (k #f))
-	  (run-exit-callbacks)
-	  (if (null? exit-callbacks)
-	      (begin (when mred:debug:exit?
-		       (exit))
-		     #t)
-	      #f))))))
+      (let ([exiting? #f])
+	(lambda ()
+	  (unless exiting?
+	    (dynamic-wind
+	     (lambda () (set! exiting? #t))
+	     (lambda ()
+	       (let/ec k
+		 (when (and (mred:preferences:get-preference 'mred:verify-exit)
+			    (not (let ([w (if (eq? wx:platform 'macintosh)
+					      "quit"
+					      "exit")]
+				       [capW (if (eq? wx:platform 'macintosh)
+						 "Quit"
+						 "Exit")])
+				   (mred:gui-utils:get-choice
+				    (string-append "Are you sure you want to " w "?")
+				    capW "Cancel"))))
+		   (k #f))
+		 (run-exit-callbacks)
+		 (if (null? exit-callbacks)
+		     (exit)
+		     #f)))
+	     (lambda () (set! exiting? #f)))))))))
+