If you start with the left timed button, you can get them both activated at the same time...
I've not beaten level 14 yet either.
Edit 1: Have both platforms in the centre and wait until the left Failed-Experiment is turning left to press the left-timed-button.
Cross as fast as you can without being caught and press the right-timed-button.
The timed section of level 14 is now over and getting to the end is now simple.
The ending door can only be reached by stepping over a slimed tile.
If you don't succeed, wait again and try again, that's how I finished level 14.