@whale

What I refer to is the part at like frame 160 where you lie on the floor.

Your weight is put on your left hand.
You swing your left leg up to kick uke.
You could gain additional speed from raising your left shoulder and I think if you were in a good angle, that could easily be a boomhit.
Problem is, you are not in a good angle so kicking his leg is the best thing you can do.
Kicking ukes hip with your shin is not as dope as a boomhit I'd say.