His weight was way off for the modified kesa gatame he tried to hold onto, and his head was too high.
Now, he probably would have improved his modified kesa position, but he couldn’t because his head was being forced up since the bottom guy reacted quickly to the guard pass.
When this happens there is no point in committing to and forcing the hold, the position is gone, you’re either going to get reverse triangled as seen, or swept if your weight distribution gets further compromised.
Just thank the guy for the supine press and go straight knee on belly, but if you are adventurous there is also a cool arm triangle entry from there. Anyway, you really have to react to the crossface or there’s trouble ahead.