[Ref in PA]

1. The B1 looks like he made a good strip of the ball from W1.
2. The B1 looks to have tripped over his own feet and as he is falling pushes W2 to the floor (extended forearm). Questionable no call.
3. B1 makes a nice pass to B2 after falling to the floor.
4. W2 while on the floor dives backward to stop the progress of B2 starting up the floor. W2 makes contact without any legal guarding position. B2, trying to avoid W2 stops the dribble and jumps over W2, traveling in the process.
5. B2 passes to back to B1 and the play ends.

In my opinion, Ref did not call walk on B2 because he was fouled by W2 and did not call foul by W2 because he was fouled by B1 and did not call the foul by B1 because it was B1 had just made a good defensive play and the foul was a little ticky-tack. The play just got worse and worse until very obvious things were let go - all because the initial call was let go. Swallowing the whistle leads to ugly play.