Basically play until you hear the warning of the excavators an as soon as you hear it run back to spawn where the quick revive is with the hacker which youll find on a desk in the room next to the pyramid(just go up the stairs right of the pyramid) . itll either be on the first floor 2nd floor or 3rd just check all floors until you come to it !
Now your back at spawn ( where quick revive is ) theres 3 panels one of them will be flashing green this is the one you need to hack you cant miss it.
An just do this until you've done all 3.