Kung Fu Thriller

I never cared why "Mr. X" would have kidnapped Thomas's girlfriend- that's just what happened to chicks in the '80s- but all these years I've wondered how he compelled the kung fu master to walk impotently in place just yards away from rescuing her.

Finally, I think I've figured it out.

...And just in case anyone out there missed the decade of prosperity and shame, this should explain what you just watched.