Also, what Screwball does in her spare time. She's apparently a nurse. And not a pegasus. And has a different cutie mark. Maaaaybe it's not the same pony but I'm blaming Discord. And I bet most of those medical ponies use stick-on medical cutie-mark tatoos anyway. c.c
Really, the whole episode was an excuse to write and animate a MLP/Indiana Jones/Pokemon crossover fanfic. There wasn't really much of a plot beyond the synopsis ('Rainbow Dash discovers she likes reading while in the hospital but doesn't want to admit it to her friends'). But I'm okay with this, because it had a deathtrap involving quicksand, spikes, crushing walls, snakes, and spiders.