You will need a four digits code (1574) to operate the large cargo elevator to complete the next objective. You will eventually be instructed to retrieve the four digit code. Once you get to the lower floor (basement), use your laser gun again to interrupt the barriers to complete your objective. Climb the ladder on your right. Walk on the narrow edge of the wall where the laser barriers are located. The best way to do this is with your back against the wall. Fire and restore your laser gun when needed. You can also touch one and it will knock out all the laser barriers in that area, and will also give you an extra laser to fire. In order to make your final escape you will need speed, avoid fighting enemies, and timing. You will only have less than four minutes to escape. Make your escape by going up to the rooftop. There will be stairs that you must climb and small rooms that you will be going in and out to reach the stairs. Keep going up until you see the weapon resembles a lightning rod on the left and stairs on your right. Run pass that weapon. Avoid the enemies and you will see a ramp attached to the machine. Go up to it and press [Use]. Go up the stairs and enter the elevator. On your way to the next level you must jump up and crawl to the next ramp. Keep going in the up direction and you will see another lighting rod like weapon to your left. Repeat the same steps as done previously. Once you reach the top, pick the door to escape.