..but couldn't go through with the sewer level(s). Being on a timer while mazing? No thank you. In fact, fuck the whole mazing in general.
By timer, do you mean the flashing green environmental damage? You can buy environmental suits in town, and the sewers should be full of them. There's plenty of parts of the sewers to stand where you won't be affected by environmental damage. Even then, if you move fast enough over the sludge, you can avoid getting hurt at all. As an added bonus, the environmental suit also makes you immune to flame damage. :-)
Other than that, there's no timed element to the level, you can take as long as you want. I'd suggest gratuitous use of the automap and save crawling.