Your job is to score 10 headshots using an M4 (either M4A4 or a M4A1-S). Both rifles are known from their strong recoil, so fire in short bursts to be able to score a headshot. You can also neutralize the recoil by crouching or holding the crosshair, however single shots are recommended, considering that the assignment requires us to score headshots.
The map contains three interesting ambush locations:
This location enables you to have eyes on a passageway that may be used by the incoming opponents. Moreover, you can turn right to check the stairs leading to the same corridor. Finally, you can crouch next to the wall found on your left and cover both locations from a different side.
The wall on the left (see above). Crouch behind the obstacle to have a great vantage point for the long corridor. You can also approach the corner and check the second corridor for any movement from both sides.
A snack dispenser next to one of the bombsites. The location offers a good vantage point for the corridor found on your right, as well as for the Alchemy Towers corridor found in front of you. You can also turn left and cover the nearby staircase.