From Ebert's Movie Glossary:
To prove how aware/crazy/focused a movie character is, a friend will wake the sleeping character. The character will instantly, ferociously, leap up from a deep sleep and pull a knife/gun or kung-fu chokehold on his friend, before apologizing for almost killing him.
. Perhaps a better title is needed, if "Kung Fu" is too specific. Rude Awakening is one suggestion.
Enough examples have been accrued, if someone could launch this, it's Up for Grabs