into which it would be suicidal to enter, typically because of the indescribably rank condition of it. Imagine Renton's toilet, in the movie Trainspotting.
Chap 1: I say, old bean, you don't want to go in there. It's a right old kamikhazi.
Chap 2: Good show, old fellow. Thanks for the warning. I'll use this much more savoury loo instead.