In a deleted scene, Colonel Carter and Doctor Keller talk about their current romantic relationships. Keller talks about her kiss with Ronon in Quarantine (2008) and Carter explains that she's in a relationship with "someone back in Washington."
This was intended as a low budget "ship in a bottle" episode, where most of the scenes take place in one room, but building the danger room turned out to be so complicated that the episode ran over the budget.
After trying the blue door, Carter points at the red door saying, "Door number two?" To which McKay replies, "After you Monty." This is a reference to Monty Hall and Let's Make a Deal (1963), where prizes would be revealed behind doors.
Neither Teyla nor Ronon appear in this episode. Sheppard's role is limited to a cameo in the opening scene.