Rainbow Six Vegas.... stuck and nowhere to go lol

Hello,

I'm in the midst of playing Rainbow Six Vegas and I've come to a stand still...

I'm in the firehouse where I'm guessing I have to save Rivers... I see three gunmen and kill them all, but still hear one more but see him nowhere. I eventually go from near full health to dead in a matter of seconds when I'm not even being shot at.

Is this a known glitch? Is Rivers dead at this point, leading to my death?

Anybody have any idea on what to do? I searched for a walkthrough, but couldn't find anything on the psp verison.

Thanks