Finish the assignment in 2:30 minutes
Grants a 1.07 Point Modifier
For this challenge, all you need to do is kill Strong within 2 and a half minutes and either kill the guards or let them evacuate. While some of the guards will evacuate right away, some will hang around to search for you for a bit. Be sure to take the stragglers out using your “instincts” by holding down RB/R1.
The mission will end when you kill Strong and his crew is either evacuated or dead. However, when you achieve a challenge the point modifier will stay active in subsequent playthroughs of this level. So you should get the rest of the bonuses first, then start a fresh game to get the maximum amount points. Or just get this challenge, then restart.
Kill all targets with headshots
Grants a 1.09 Point Modifier
To complete this challenge, you will need to kill each and every guard, as well as Strong, with a headshot. To make things easier, you can pull the trigger halfway to slow down time and to make your aim steadier. Also remember that you can lure guards by shooting areas near them. They will enter a cautious mode as they go to investigate the noise. When they're standing around looking for you, they are easier targets to headshot.