We did a half pump - i.e. the handle was in the down position and it was pulled up (strongly). I think the person was hoping that the KO liquid would be removed from the bowl and leave the cap at the bottom within easy grasp. When the cap disappeared, they had an "oh shit" moment. Rooting around with half a chopstick didn't result in reaching it so it has to be slightly deeper. The wet-dry vac is a decent idea as it may pull it from a recessed area. It was a strong pull, but I can't see it making it all the way to the Joker. However - if dis-assembly is required then we'll have to pull the hoses off to get at anything - and I pretty much guarantee there's effluence in them.