I can't be knocked out with physical damage alone unless I'm anemic already, thanks to the instant healing. But if I have to heal a series of bouts of severe damage that would make me anemic. You'd have to beat me about the head for awhile is all.

Stuffing me in the panic room and waiting for me to run out of blood is probably the least difficult option, but if I get beat up a bunch beforehand it would speed up the process.