The problem is, if Peter was Otto? Those globs of webbing could have been bombs, or claws. And with Harry off balance - well, that was the time to strike. Harry narrowly dodged him, and Peter shot another web to keep his momentum going, using it to backflip and reverse direction. How did Otto get around? Was his mode of transportation as flexible as Peter's, or a little more structured, like Harry's?

Peter came at him again, this time from above. Alternating direction was one of his tactics for distraction and disorientation. If the enemy couldn't guess where you'd be coming from, they couldn't prepare.

He also hasn't factored in Harry falling. That's a worst case scenario that would probably end in Peter diving to save him, for obvious reasons.