Hop back onto the staircase and head up the flight on the left. Instead, jump onto the boxes on the right side, and crouch to find the next blue light behind the cylindrical tank. Next up, walk towards the staircase on the opposite side of the room, but don't run up the steps just yet. Stand as close as you can to this box and aim-down-sights into the opening to the left of it to shoot another blue light.
Head past the blue rabbit toy and look for an electrical box on the wall with a faded yellow sticker. Now it's time to run down some more steps, taking the next set of stairs to the left of the Pack-A-Punch machine. Take out the orb of light tucked away behind the grate. You can find the next one by running down the same flight of stairs, and crouching next to the metal grate on your right. You should be able to see a blue light behind the chair, which you need to shoot until it disappears. Walk forward, and stand in front of the gap between the two terminals, where the orange chair is on its side. Then turn right to run up another flight of stairs. Starting at the Pack-A-Punch machine, turn around and run up the stairs. NoahJ456 managed to complete this by searching for five blue lights, and shooting at them in order I've laid out below.
We're now about to take a short detour from the main mission to check out the bizarre zombie 'coffin dance'. Once your Pack-A-Punch machine is up and running, you'll be transported back to the normal version of the world.
