That doesn't make sense to me. Then again, Rudy taking the time to use the bathroom in the first place, assuming this was indeed a burglary-turned-murder, makes no sense either.
I do not believe that burglars, as a matter of course, spend any longer inside a residence than is absolutely necessary. I can only see a burglar leaving a bowel movement behind in one circumstance: they have good reason to expect that they are very unlikely to be disturbed while committing the burglary (e.g. your typical vacationer who arrives home to a burgled house).
After he purportedly climbed in Filomena's window, Rudy both left his feces behind and ransacked her room. I find it highly implausible that, within moments of breaking in, having trashed the room looking for valuables, he interrupts his search to take an urgent bowel movement. If his stomach was distressed immediately after entering the room, then he would have either: 1) gone to use the bathroom before commencing the search (if he figured that no one would be there the rest of the evening), or 2) sucked up his discomfort and searched for valuables as quickly as possible, then fled at high speed for the nearest toilet or poorly-lit shrub (if he figured that he might be disturbed at any moment by someone arriving home).
Moreover, using the bathroom first would place him in Filomena's room when Meredith arrived home. In that case, the most obvious point of egress is back out the window he just came in - NOT the front door, whose use entails a much greater probablity of discovery by Meredith. Furthermore, if he used the bathroom before trashing Filomena's room, then there is no reason for him not to flush the toilet afterwards.
Perhaps. But if he was in that agitated of a state of mind, then I'm left wondering why he took the trouble of locking Meredith's door if a rapid exit was the only thing on his mind.
Not to me they don't.