everytime i go through the last tunnel right before you reach the pedestal that takes you back to the mansion the rocks fall on me and kill. ive tried it like 20 times. whats the deal?

It's weary hard to make it. First of all make sure that the game runs at max speed, so if you got a week PC turn the settings down. Secondly don't jump, becomes it slows you down a lot. Run the the shortest way. Getting scared also slows you down, so watch it.
I made it after the 6 or 7 try, so keep on trying. You'll make it eventually.

Sorry, but I can't really remember...

Yeah the ending is really frustrating. I used svcklead's patcher to increase Jack's running speed for this part, because no matter how well I ran I could never make it.