try using a really small flathead screwdriver and sort of jam it into the side of the top of the screw stump, then try to spin it laterally as if you were spinning a prayer wheel or a toilet paper roll or something. When I did it I couldn't grab the stump with pliers so this was the only method that worked.

Alternatively you could just try to VERY CAREFULLY super glue something on top of it and twist it off as it should not be torqued in there much at all anymore.