Payback
Get out of there, the man is obviously dangerous and/or crazy.
Nothing. Just stand and pray to every God known to man that you'll return home in one piece.
"But, I'm not holding you here," he began. "I merely wished to show a poor, helpless couple some hospitality..." He eyed them dangerously, a smirk forming across his facade. "Of course, nothing is ever truly free. I will expect a little payback."