Let's not forget that the Empty is out there, or that Nick is still in play. Michael's demise was way too convenient, and he could well be lying doggo, awaiting his chance to infect either of the above questionable characters. There are a whole bunch of ways the big bad could go.

Of course, given the standard of writing in this season, and especially in this episode, it's just as likely to be stupid as it is to be innovative and brilliant. *sigh*