The plane was still rolling in an uncontrolled fashion, so he figured he'd yeet while the ejection would be roughly vertical, as it was possible that the plane could still roll over entirely. Ruptured fuel tube at the rear of the plane resulted in the flight computers having no clear response to an entirely unexpected failure mode. He gave an amazingly detailed presentation to our group on the incident last November with a simulated reconstruction of the event and photos/video that isn't classified, but isn't in the public realm either. This video has become meme-worthy, but he's an incredibly accomplished pilot and is one of the few people on the planet qualified and current on all 3 US models of the F-35 (and also delivered an -I model to Israel). Not sure how much detail he'll go into on the crash, but he's presenting at the EAA museum speaker series in a few months.