It looks like a lock release pin. Think of a bathroom door lock set. When you go in and close the door, there's a button on the door knob to lock the door. When you turn the knob from the inside, the lockset opens. When a child locks themselves in the bathroom, the knob on the outside has a hole in the center that you can insert a pin (such as the one in the OP) to unlock the door.
It's probably not for the head door, but maybe opens some kind of lock release.
Ted