I'm ashamed to say I struggled with this lol.
In the end I managed it using Flight, I flew to a roof, and did a double assassination, flew back up and repeated, this was ONLY after clearing out the snipers on each wave first, and I used Wolf Pack as soon as it charged.
Arcade Crazy - 26 - Over Achiever - 54 - XB1 Points - 402
Enthusiast/Fanatic - 5
Franchise Clubs - 9x Tier 1, 6x Tier 2, 1x Tier 3, 1x Tier 4
Staff Clubs - 12