Hmmm... looks like a really long con for 20+ BTC. Bought an account more than a year ago, built up trust (possibly with puppets), although the exit scam doesn't seem to have been very successful. This could have
easily gone into triple digits if Master-P had a bit more patience and foresight. Me, cynic? Nah...
Don't think any escrow would get up to 100 btc held at once. Maybe to escrow one big trade, but that wouldn't be a good one to steal because 1 person stealing 100 btc from 1 person is the easiest way to have someone seek retribution, help from the authorities, lawsuit, whatever.
Stealing a small amount from a bunch of people that isn't worth any 1 person spending money to get it back is the play.
As for why now? Maybe he needed christmas money, maybe he or one of his alts had a big payout due that he couldn't/didn't feel like paying out, or maybe business started to slow, so like dooglus explained it's time to shit or get off the pot. Steal 23 btc now or hope the amount held gets that high again in the future or wait years to earn that back.