The slowest moving thing in TF2 is the Heavy with his chaingun lowered. I walked across the entire map of Badlands that way and it took 53 minutes. I had exasperated Medics along the way trying to heal me, with every one of them jumping off after a while. I was like a slow moving train, and no one wanted to go too far.
The second slowest thing (in this world too I believe) is a teleporter still at stage one infancy. A baby teleporter. Squatting on a slow teleporter allows you to see all your teammates, though, one by one, as they approach with the same look: get off and allow them on.
The third slowest thing is your reaction time when you realize you're standing in stickies. The fourth is lag. The fifth is the Overall Timer if you're losing. The sixth is any amount of spawn time. The seventh is the amount of urination time wasted during a critical part in map/server history.