I was just looking through the Walkthrough for the dewmo (I already beat it, I was just comparing how we did things different)
I found out, in the lava room, you can jump those 2 gaps....I guess I did it the hard way, I timed the exact time it takes for the lava bursts to go off, jumped off, and then the made me fly all the way over by the bridge that falls down....this hurt very bad, and almost killed me, but it sure was fun, you guys should try it!!

http://www.geocities.com/TimesSquare/Bridge/3528/indy-front.gif) Dark Indy http://www.geocities.com/TimesSquare/Bridge/3528/indy-front.gif)

what I found out is that if you jump over the falling bridge, all three elements of the bridge fall down, if you touch them or not... But feeling the lava really is great fun :-)