So something interesting that just came up which probably hasn't been on anyones mind for a while was the ability to slide open/slide doors such as the Blackhawks, or even just to open the doors of a HMMWV for cover.
Some of you may wonder why such a thing would even be necessary at all. For one, if you could slide open a door coupled with the possibility to fire from the vehicle it would allow you to give fire support from within a blackhawk via overhead to your team.
If you're in a HMMWV & you had to dismount due to contact you could use the doors of a HMMWV to engage contact without taking too much fire (Or in the case of ArmA 3 at current a Hunter/Efreet)