He used a crate before touchign wall 4.
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Rules
Walls before attack (WBA): You must touch all the marked walls before you're allowed to attack your opponent.
Crate before attack (CBA): You must collect at least one weapon crate before you're allowed to attack your opponent.
Attack from rope or parachute (AFR) (AFC): You can only attack while hanging on a rope or while using your parachute, unless the weapon that you're using doesn't permit that.
I got a crate, touched 3 walls and then used switch worm for the fourth wall then attacked.
In the rules it doesn't say you're not allowed.