Questions about engineering and deconstruction time.

[pscbird]

I�m thinking about getting the Adv. Engineering cert. Do any of you old Vets know:
1. How long does a mine/spitfire stay around after you have placed it? Until you log off?
2. If I just drop something, like a med kit or an ammo box on the ground, how long will it stay there before it deconstructs?
3. If you put a motion detector next to a Spitfire turret will it fire at enemy inviso�s who move within range?
Thanks, Rada