Find a group of people you trust on xbox live, like homies you've played with for awhile.

Get everyone to have a gold key ( for fastest results ) by signing up on Shift. ( In extras on the main menu. )

Player one will again be the one picking up all the items ( to be split up after you are done glitchering )

Have the party, one by one open the chest and have player one grab everything. ( Important, everyone should stay near the box, to prevent an auto-save. )

Then have everyone besides player one, dashboard. ( Player one can wait in game with the guns )

Now because everyone dash boarded without saving, they will still have their keys.

You can repeat this process as much as you want, just watch out for those autosaves, they'll get ya.