At my old skydiving club an instructor was taking up some first timers and was kneeling looking out of the open aircraft door at 3,500 feet as they were running in. The students were packed in behind, one of them stretched, and kicked him out of the door . He said afterwards it came as a bit of a shock, too ! (actually I seem to remember him using somewhat different words). He wasn't planning to jump on that particular sortie so it was impressive he pulled his chute within about 2 seconds of his unplanned exit.