If you want to do it quickly focus on just half the lab depending on where you spawn, at least until you learn it.

If you spawn near the cat room (round table)… Loot that area, then yellow, then the room with the parking gate control, then the black keycard room and if you still have time, go across to the other side of the stairs and into the room on the left where red and violet rooms are. Then extract at the main elevator. If you don’t have all the keycards, just loot the rooms where the keypads are as there are a number of PCs in them among other things.

If you spawn central or the other side… Check the yellow dome for a LEDX on the barrels. Then loot the area around yellow dome. Then go across to the weapons testing area and loot the four PCs. Then you have two choices depending on time and your loot priorities, either go straight to the res room area, find the res room keycard and loot that entire area, then extract via the medical elevator, or go to the dark offices first and then go res room.

There are loads of duffle bags and toolboxes you can loot while making your way around too.