Is this the intended solution? Spoiler Falling trick onto R, wiggle slider so B falls and can walk to the win?
@Block builder in my case Spoiler your falling trick was based on autopilot technique moving the draggable.
@Block builder Spoiler tap on the draggable, once you are there tap on the right stone block. When B starts to step on the first stone block (before turning to the right) move the draggable to the right. B will think he continues on the original position so has to walk to the right one tile which doesn't exist anymore.
I was close but I didn't do the wiggle - thank you Block builder. Thanks Ricko for the level that is also very small.
Formi it was the trick that @chemi described. Been getting B to fall off R's head, away from the zapper but still on the platform was the tricky part. A big Challenge in a little tiny space!