A tip on the last mission (heatray) on chapter III.
It's a 4 vs 6 dm map.
Use increased health card as it will give you 140 health and your team will own the other, easily.
When the darkwalker spawned our team was ahead with 7 kills.
The problem comes when they take the darkwalker but just stay in the back alley where they can't reach you and they will be reduced to 4 or 5 players (1 or 2 using the dark walker).
Order the bots to cover you and the rest basiclly solves itself.