Locked Out
There's something about a locked door that just irritates her. She's used to the boundless freedom of flight. The thought that there's somewhere she can't go just annoys her.
Unfortunately, that 'somewhere' is Applejack's room, meaning she's going to have to get creative. Captain Honesty may not be the hardest pony to trick, but there's hell to pay when she catches up with you.
As Rainbow Dash ponders whether dynamite or drills are quieter, Applejack sits on her bed and stiffles a giggle. She shouldn't play such mean tricks.
But Dash is just so cute when she thinks she's smart.