No it isn't. Um... lemme think.
Just prior to this, you enter the room with boxes & a tunnel full of manhacks to the left, yeah? Well, when you enter that bit, you need to head across to the opposite broken stair, and hop down. Should find a door there or therabouts.
Basically, head down till you find an open doorway. IIRC there's a set of crates on a ledge underneath the level you find the doorway at (the crates are at the bottom of that brown pipe, you need to shimmy on over a pipe to get to them; I never did that cos it looked a pain in the arse). If the staircase above is broken, it means you're not supposed to get up

EDIT; oh, and you may want to put on subtitles... for me, I encountered the nefarious stuttering bug (including 2 outright crashes seconds before the ending sequence); also, I think the subtitles are sometimes shown when the corresponding speech is too faint to hear; a bit annoying but also useful if you can't be arsed hanging around.