Typically, we think about passing a knot that we come across mid descent. But what if your casualty is stuck right on top of the knot?! Often the rescuers instinct is to try and haul the casualty up to create some room between them and the knot, but with some extra gear (Grillon or some other adjustable/releasable lanyard) we can essentially "pick" our casualty off their descender while we stay under the knot, this makes for a timely rescue and minimal effort! This is a L3 skill for IRATA and L2 skill for SPRAT.