Damn, that was a rough start. If you'd gone out into the room you'd probably just have died horribly.
In my first playthrough, I did exactly that, and that's what happened.
Time for the next update!
Part 020 - E3M2: The Cesspool
I wish we had more of a breather after the last level or at least some time to rest. This level, although not as brutal as The Storehouse, is still pretty difficult. Save your items for when you really need them. I recommend the invincibility ring for the very last batch of Disciples and possibly the very last enemy, if you know what I mean. Further, this level is quite symmetrical so use this to your advantage. Enemies will rarely follow you to the other side due to the length they have to travel to get there, so for the most part you can lead them from the left or right to the middle and deal with them one by one by forcing them through narrow corridors. Finally, I realize I do something really idiotic in this level, but it was amusing to me so I didn't re-record it. I'm sure as hell not going to play the game perfectly, but I will have fun.