The moment Malcolm offers up his room is the moment Tim makes a break for it, nodding with steely determination because of what needs to be done. His attention is everywhere and nowhere as he trudges off--

he doesn't think Steve Harrington is around, noting no loud shadows or lights under closed bedroom doors.

An indecipherable noise makes him turn worriedly back to the pair of men, but... Tim opens the door to Malcolm's bedroom and closes it behind him with a click. Sorry. Sorry; he'll undo the lock in a minute. Once in the locked in-suite bathroom, Tim even keeps the heaving and retching silent. He's considerate like that.