I thought this too, initially (as did a wide swath of the news media covering it at the time). He can not.

The $1B is for a different scenario; he doesn't have the option to back out of the deal voluntarily.

https://www.cnbc.com/2022/05/13/elon-musk-cant-just-walk-awa...

> A reverse breakup fee paid from a buyer to a target applies when there is an outside reason a deal can’t close, such as regulatory intermediation or third-party financing concerns.

No, he can't. He's on the hook for 1B if the deal falls through but he has no right to cancel

Given where the markets are today, Twitter is a ~$30B write down for him once the deal closes, so if he could pay $1B to make it go away he would have done so already.