In Big Oil Heist Day 1, what's the use of the key linked with green ribbion?

[Yakumo Yukarinovski]

I have found that type of key, which is not a escape plane key.

Bain didn't describe for that once I grab, and that key does not interact with anything whether on day 1 or 2.

Usually you can find more than one key on day 1.

The appearance of that key below:
http://i.imgur.com/QdVXSrx.jpg
http://i.imgur.com/YBHeajI.jpg

Since I can't find any topics related with that, anyone got an idea?

[OhGod!YetAnotherGuyWithALongName]

It's related to the new DLC. 2 Keys & a box IIRC

[Ћ Abomination Jones]

Purely a thing to do with the Spec Ops DLC. You find two keys and a case on the heist and you get part of the gun from the DLC. Do all 4 and you get the gun completed.

[Yakumo Yukarinovski]

Thank you for answering, can't wait to unlock those cool attachments once I get the new DLC.