Shooter landing on defender laying on floor

[CJP]

With 5 seconds left in 2nd quarter, A1 is shooting a free throw. The ball comes off the rim and a scramble ensues. Players are on the floor. A2 gains possession and gets a shot off before buzzer. When coming back to the floor, A2 lands on B1. B1 did not slide or roll under A2. A2 rather "floated" over B1 while in the air. I had a no call. There was some discussion at half time that it should have been a foul on B1. We agreed to disagree, it was only a discussion.

I am looking at rules and case plays trying to find an answer. I am okay with a no call but following the logic in case play 10.7.1 a foul could actually be called on A2.

Thoughts??