I'm going to guess that all of the cybruisers dying is what triggers this event - in which case having to wait quite as long as I did is far from ideal. I was pretty convinced something had broken in the map as I as shut out of the chamber for ages, trying all sorts of switches until it just (seemingly) arbitrarily let me in.

I'd force the death of the cybruisers as part of the scripting there and make the sequence end quickly, so the player doesn't end up wondering what's going on.

Sorry, I'm not sure what you're saying here. Is the gas sequence too long?

Doesn't the camtex help already enough to make the player get what's happening?

Well, when I played it the camera showed the monsters being gassed and most of them dying. However, the sequence didn't end. I'm pretty sure one of the cybruisers had managed to survive and was tromping around the chamber trying to get to me as I ran around the map to find out what I could do to clear the gas and open the door. It must have eventually succumbed and died at some later point because the door just randomly opened after a few minutes.

It'd be better to control the deaths of the cybruisers so that what happened to me isn't possible.

You can activate the chamber as many times as you like, though I agree that the monsters should be dead by the end of the first sequence activation.

If I can read this right, what he is saying is that the door isn't opening for him for an extremely long time, due to enemies being alive.
I dunno if it changed since I last played it, but that sequence should end after a set time IE it has no trigger in actors.

It's me, I tried fixing it by adding SectorDamage calls to the script, but apparently messed it up and I did not have the time to solve the issue yet since a storm decided to fry my modem maybe ten minutes after upload.