In "That Which Survives", Kirk and McCoy are taking a nap when Sulu is attacked by Losira. He has his tricorder on the "burglar alarm" setting, which seems to do nothing; she just snaps it off. Kirk and McCoy = zzzz. Then Sulu fires his phaser at the ground, causing a big explosion. Kirk and McCoy, still snoozing. Losira touches Sulu, causing him to scream. Nothing. Then, and only then, Sulu yells for help; Kirk and McCoy finally wake up.
What, explosions and phaser fire won't wake up Kirk? But Sulu crying out his name does? Makes you think.
What, explosions and phaser fire won't wake up Kirk? But Sulu crying out his name does? Makes you think.