Have you tried this?

[Anti.Enemy]

once you are inside the tomb of qualapec, get into the place where the ball will roll down, you can get through without openning the three gates, so what you have to do is run as fast as you possibly can, and start rolling to the left, once the ball falls, it will roll to the right which gives a small space to the left where you can roll in it,
you can get through the other side without opening the gates, but unfortunately if are on the other side, lara will automatically die after a few seconds.. :(
but try it its fun :jmp:

[Tthe Spirit]

I did this a while ago... i noticed the same thiing as you to... i thought, maybe i can escape and i was curious what to do if i get stuck, then i was like :yik: to see her dying...

[thevman]

I've made it as far as the back paths around where the ball starts from, but she always fall dead there, shame, it would have been funny if you could skip the whole level like that and get right to qualopec! :p