ShadowPatriarch: Yes, the bathroom isn't going to yield any substantial evidence at this point.
Whatever info the coworker provides, in my opinion, will just be hearsay.
Have you considered the possibility of there having been 2 potential murderers? As in, Archie came first to the room, had an altercation with the victim in the bathroom and in what ensued Archie panicked and left her for dead there, when she was but unconscious. But then came in another murderer who actually finished the job, and that is why Archie is so taken aback when seeing all the blood around Darlene.
bler144: Re-reading the OP, unless there's actually something stuffed in the drain (krypsyn's confession note), yeah, I'm happy avoiding the bathroom for now. Agree on the hearsay.
For me it's bedroom, but mulling over a few details I'd at least consider the bigger moonshot of the maintenance man.
The >1 murderer theory would fit a number of details in the story (why Archie headed toward the bathroom but didn't turn off the taps, e.g.), not to mention the suggestion that there's a "surprise twist" in store.
Though with 1 murderer the motive is moderately clear (jealous BF, regardless of who BF is). With two murderers the motive of 1 of them is at least less clear, though perhaps the doorman's testimony is a hint.
I do have a vague theory on why the taps were turned on other than what the prosecution has proposed.
Yeah, Maintenance Man seems odd, unless he can either give indications on when the flooding started, or if some evidence has been stuck in the pipes, like a small knife (or just the blade of it).
And the idea that there is more than one murderer seems interesting, though so far nothing seems to indicate it (which may or may not change with further evidence).
There is also the option that Archie was just acting shocked, at least well enough to fool Dean (as he was described as a rather clueless guy), and just wanted to make sure to leave some
more fingerprints in the bedroom (which Dean would then confirm to have happen when he searched his button), as a way to justify the discovery of possible fingerprints on the crime scene...