I'm sure most of you will already have him already but I'm just helping out in case others don't and want him.
All you need is three people, one of them can be a guest in on your xbox.
1. Set up a private game
2. Set it on Capture the leader (no bots)
3. Invite a friend who is willing to spare about 15 minutes
4. Pick the map Overpass
5. If your guest isn't the leader(they usually are), get them captured and go onto the next round so they are the leader
6. Run up to the turret place your leader facing against the sandbags by the turret
7. Get your friend on the turret to keep shooting the leader
8. Keep reviving the leader
Hope this helped