Well, theoretically you could make an offer, that raises the share price to the offer and then you can cancel the offer and sell your shares fornthe high price and profit.

However the SEC would investigate very carefully. Especially in the case of Musk, who has a history of stock manipulation. He'd need very good arguments.

However there was something else: After his offer markets crashed to some degree. Thus he overpaid compared to what he'd have to pay, if he had made the offer a few weeks later. So maybe he only wanted to lower the price.

It's likely that the initial offer came out of a rage. Just see the back and forth with him joining the board ... or not. However the key point is: He's not a poor victim who was forced to buy something he didn't want at all, but he initiated this and signed papers about it. The court just decided that he can't get out.