Its Like Christmas!

Hi, me and my friend where trying to maximize our number of armory entries by playing marcus missions twice on each others character (that probably didnt make sense.) So some how when we started the timer my Its Like Christmas! mission got glitched.

My point is- if you can help me do the mission unglitched that would be awesome. And I would let you take all the loot I'm  just trying to get the achievement.

Im on the 360 and my gamertag is RELLEKER. Just send me a message if you can help Thanks