One little gag I added in my War of the Stars first fanedit (I don't know if many people understood it well though) is that it is Obi Wan who accidentally starts the converging garbage compressor walls. He does it when he tries to shut the beam tractor down, but obviously he makes a wrong manip.
You could go over the top with this idea, like maybe having Obi Wan pushing the walls to converge (not knowing what he's doing) and R2 trying to stop them. That could go on for ever.