How do you gain access to Drax's office?

When you get to his office you have to follow the wire from his office door to the duse box which you will activate, this also activates the sentry guns which you will then need to disable. To disable the sentry guns you will need to go in the door across from the door that you came in through. Deactivate the camera across the room using your watch and enter the room on the right. Take out all the people in the room, making sure they don't set off the alarm. At the far side of the room there is a vent that you need to crouch down in front of to pull open, go to the end of the vent and you will come out in another smaller room. There is two different panels of buttons in the room, go to the one on the side of the room closest to you and hit all the buttons, this will deactivate the sentry guns. Go back the way you came until you get back to Drax's office. You will have to take out two guard s that have surrounded Dr. Good head. Use your phone to figure out the code to his office, punch it in and you will be able to enter.