various /obj/machinery/marine_turret exploits

[mullvad]

Bug Description:

The /obj/machinery/marine_turret will spawn an alert() whenever it requires user input, but does not properly verify if the user is still allowed to use the /obj/machinery/marine_turret after the alert() has finished.

Steps to reproduce:
1. Walk up to an /obj/machinery/marine_turret
2. Open the interface
3. Select burst fire.
4. Keep the alert open
5. Walk away
6. Click yes
7. You now posses telekinesis!

[Eenkogneeto]

This can be used to make a movable turret thats still on and capable of firing, But its not terribly well known how.

[phil235]

fixed