Ok, so I’ve come to the same conclusion @NigelG did in another post:
The best solution is using an HTML element set to iframe with a javascript timer inside. Any internal Bubble solution would require data to be changed every second, which creates far too many workflow calls.
I used this easy little java widget here:
http://www.hashemian.com/tools/javascript-countdown.htm
The final message is set to “Time’s up! This is your last question.” The next time the user clicks an answer, I’ve set a workflow condition to check if the difference between the User End Time and Current Date/Time is less than zero, triggering a popup that ends the quiz when exited, as opposed to a new question being displayed.
That’s my solution, hope it helps!