The MM is (8% * 50,000 USDT) = 4,000 USDT. The IMV started at 5,000 USDT and has now dropped in value to be worth 3,000 USDT. Since the MV is now 1,000 USDT less than the MM, the position is automatically liquidated as soon as the MV becomes less than 4,000 USDT.