Hello and thanks for the report!
I have run across similar physics behavior before, but decided to take a look a this issue specifically this morning. Some findings so far that I didn't know; when stuck on the power attack animation, switching to bow and then kicking can allow you to move freely again. Flying out of the arena I was not able to reproduce this time, but it's certainly happened to me before, and continues to happen to Spidertrons given the right conditions.
I'll make some notes on our bug tracker based on all of this. Thanks again for the awesome report!