When Joey is in the interview room with Detective Benson, Stabler and Dr Wong he becomes visibly distraught about not sleeping as he goes up to the window screen. When Dr Wong goes to settle him he at one point has both his hands up to his ears. He does take his hands slowly down in the continuous scene but as it cuts to another angle, Joey's hands are back over his ears before being lowered.
When Detective Benson and Stabler go with the crime scene unit to determine if the janitor could actually climb out the window and to determine other aspects of the crime, it was a Saturday. However when Benson found the gun in the furnace the gun was severely melted. Being a weekend, the furnace wouldn't have been on for a day allowing it to go cold, so the gun couldn't possibly have melted.