You can hit people from a distance with mystical chi power, but, for some reason, it only works on your own students (resulting in an embarrassing loss to an MMA fighter who seems impervious to your attacks). Then, you use chi power to harden your skin against the strikes of a blade – only to end up cutting yourself badly. And, now another ‘chi’ master has the same problem – he just can’t seem to affect anyone but his own students.
As the Skeptics Guide to the Universe points out, it’s probably a shared delusion of both the ‘chi master’ and his students. For the students, I’m sure it’s terribly intimidating to have your instructor (who often seems larger-than-life) tell you he’s going to knock you unconscious, have a history of ‘knocking people unconscious’ with this move, be up in front of everyone, and have him do this technique to you. If you’re a true believer, there might very well be some psychologically-induced physiological effects. Further, his students seem to fall in a self-protective manner (which indicates that they aren’t actually unconscious). If you’ve ever gone unconscious, or seen someone go unconscious, they often drop a little differently – sometimes their knees buckle, sometimes their head hits the ground – because when you’re unconscious, you’re not in control of your body. There are some parallels here with being “slain in the spirit“.