(1) Crossing the administration building Deus Ex: HR Guide

Start with examining terrorist's corpse and exploring a room in order to find combat rifle ammo and sniper rifle ammo. Now you can exit the server room #1 and head towards the elevator (Head Office) #2. Use control panels and wait until you get to a new level.

Exit the elevator and go straight ahead, ignoring fights which can be seen under a glass bridge #1. Once you reach a staircase save the game and go upstairs #2. After few moments you'll get close to the part of the building occupied by enemy units.