Jim is right... thats why I usually suggest crashing the kite in the water first to KILL it ... grab the o-shit handle (god please remember to undo the velcro... I usually leave mine undone), release your leash if you can't transfer it, and THEN pull the QR. I had to do this a few months ago at backside when my bridle snapped and my kite started looping. In between the loops, crashes, and relaunches I managed to grab an outside line and release everything else.

If you know it's getting crazy (dark clouds coming, gusty weather, slightly overpowered, etc) then you should already be rigged with the leash on the outside line.

I use the center depower because I've been trying a lot of unhooked stuff and dont want to keep crashing my kite... that becomes a hazard for everyone else.