None of the neighbors said anything about the sleepover guy being angry or unruly...you would think they would have, if he too was acting up. The complaints seem to have been against Kortne. Not sure if that means anything, but anyway.
ETA: Also, if one wants to go with simplest answer, neither apartment answers when LE knocks=LE didn't knock.
yeah. they probably didn't knock. they had just been there. I am pretty sure they wouldn't knock on TS door. it was late and he was trying to get some sleep. in LE eyes this entire thing was a nuisance that could be solved by people just going to sleep. Assuming that LE knocked on TS door and him not answering is assuming something we just don't have all the facts to support.