TF2: What code does Soldier put into the door keypad in "Meet the Spy"?

In the 'Meet the Spy' video from Team Fortress 2, the Soldier character puts the code "1111" into the door keypad as a joke, highlighting his lack of understanding or creativity. This is meant to be humorous and showcase the Soldier's simplistic and straightforward thinking, as he assumes that a single repeated number will be sufficient for security. The choice of "1111" as the code further emphasizes the Soldier's lack of imagination, making it a comical moment in the video.