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Putting a ice bath (not much water) in your cooking pot and remote start should work. Practice by loading up the pot with ice and see how long the pot stays below 40 * F. That will give you an idea of thaw time for food safety. The adding of an hour or so to your cook time because the pot is going to take time to go from 40* F to 118* F.
Butt was within the time and temperature limits 4 hours under 140. Should be okay because the internal was up to 170. Nolaegghead's idea of foiling and cranking the temp up should work. Just will not have a "Bark".
REMEMBER tough and "dry" pulled pork is usually under cooked, I take it off at 200 and wrap it and put in a warmed cooler to let the juices redistribute for an hour at least.