Im wanting to place an order with a questionable MDMA vendor due to his proximity to me, everyone is yelling about him having shill accounts. which really do make sense, but it's full escrow I don't know how I would be out BTC besides it auto finalizing. So will someone tell me how I would get scammed buying MDMA from this vendor if thats what the escrow system is all about?
You wouldn't, that's the point of escrow. You don't pay until you are happy with your order(it's in your hands).