What is the purpose of this sentence?

Lock the door on your way out?

On your way out" means "as you go out/leave the room, or the building". Most often this would mean that you should lock the door after you have gone out of the building and shut the door behind you. So "lock the door on your way out" really means "Lock the door immediately after you have left the room/building". Which means that it can definitely be considered as giving an order.

depends on your school

when i was in high school i took ap biology my senior year and it was the hardest one for me because my teacher finished the material within the first month of school and then went on to doing advanced college level it was horrible. but at a nearby school ap biology was one of the easier aps. also, it depends on what you are interested i like math a lot so ap calculus was easier for me than most but i hate history so ap us government was harder for me than most.