Probability #999: They're doing a coin swap and withdrawing theirs to swap with a new coin via an exchange of their choice (They need a leverage for an exchange to host their token swap event, hence they put a chunk of their coins in to drive volumes).
Probability #998 : Buying their own coin cheap, as after the news it will explode and can just make it 10 times... they don't need to empty even if they ran because noone can do anything to their wallet even if they want.