Firestarter, Day 2
Day 2 tasks you with stealing information on the Mendoza family...from an FBI building. Things really can't get much more dangerous than this.
A stealthy approach is key here. Stay low and keep moving along the side of the building to enter a side door. Take your time here, and you should be able to knock out a few patrolling guards as they pass by. Once inside, you need to find the server room. This is a big building, with lots of rooms and hallways, so finding the server room can be a pain. Stay low and keep moving, and you'll find what you're looking floor. Note that you'll need to disable the alarm via computer and alarm boxes as well.
Once you find the server room, get inside and start working on the security door. This can be done with a drill, handsaw, C4, keycard, or ECM jammer. The last two are the quickest and quietest, but you'll need to find the keycard or equip a jammer to do so. C4 is not recommended for a stealth run, but a handsaw or drill will work. In that case, however, be sure to avoid letting guards investigate the noise. Once through, grab the server and make a break for the getaway van.
Should stealth fail, the server room makes for a great entrenching spot. Get inside, drop a Doctor Bag and Ammo Bag, and hold off the assault via the one doorway in. Also, note that a shutter will drop inside the server room, forcing you to drill a second time before reaching your prize.