They can digitally fix glitches if an actor blinks or twitches (if the budget's big enough, of course!). Joss Whedon mentioned doing it in Buffy when Joyce blinked once after she died; and also in Firefly with Mal. Not that Mal was dead, but that scene in the pilot just before the opening credits, the really long pan-out on Serenity Valley with Mal staring in disbelief at the world crumbling around him? Yeah, he blinked once. It was a really long shot.

But they fixed it. So I guess goofing as a corpse wouldn't be the end of the world, they could just re-deadify you in post-production.