Assuming that what he is saying is actually true, and not some clever ploy (probably true but you never know), this cagara guy is heavily long ETH and heavily short BTS. He probably could get margin called bi EITHER an ETH crash below 250 or a BTS rise.
For example, ETH dumps harder -> his collateral value goes down -> he cannot hold the BTS short -> he is forced to cover, driving it up hundreds of sats.
I think this guy has had plenty of time to cover his BTS short, even on drops, when he could have made a gain. What is he thinking.