Mistake of Pythagoras Help

[bnlsla]

Im stuck at the part with the 2 triagle things that hail down head crabs, ive shot them down and killed everything but i cant get any farther, theres the computer terminal but nothing happens with it and the doors dont open. :frown:

 

[bnlsla]

*Spoiler*
nevermind, found out it was just a glitch, i reloaded from ealier and now alyx is with me

 

[Isamu]

I apologize for bumping this but I am stuck near the same area. The problem isn't getting Alex to open the doors...I did that already. But it's what comes AFTER that that's a giving me a headache!

That round flying cylinder is IMPOSSIBLE to kill without dying from the ZILLION hacks and headcrabs that keep spawning over and over again! I keep shooting rockets at the darn thing, but it won't explode.

What am I doing wrong? Is this thing even supposed to be shot at with rockets? If so, where exactly do I aim, and how many rockets does it take to bring it down? Every time it glows that green lightening stuff, more and more hacks/zombies/headcrabs keep spawning.

Sheesh...talk about a PITA! HELP :rolling::sniper: