Who wants to bet they didn't learn what a batleth is from a training video? "Let's see, we've covered the hot dog rollers, proper bathroom key procedure and the optional bathing policy, looks like we just have to watch the video on science fiction weapons and the appropriate counter spells to defeat them.."
The second clerk knew the counter spells, how else was he able to tell the guy with a sword "no, I'm not going to give you the money"? Seriously, IIRC isn't it against 7-11 policy to fight back or refuse to pay a robber, don't they fire people for refusing?