Murdoch: He was always going on about Skyrim and Old Republic. You are talking about dorky role-playing games right? You must be into those, huh?
McGee: Until I took an arrow in the knee.
"I used to be an adventurer like you. Then I took an arrow in the knee" is an often-repeated stock line from the role-playing video game The Elder Scrolls V: Skyrim. It is said repeatedly by town guard non-player characters throughout the game, and it went on to inspire the snowclone meme "I used to X, then I took an arrow in the knee."