(2) Peaceful option: Securing the administration building Deus Ex: HR Guide
Last update: 11 May 2016
Warning! If you want to avoid killing or even stunning your opponents for all costs, read a description below on how to get to the lover level (air vent). Then scroll down to description of Step 3 (Getting to Sander's location).
Stand near crates and wait for opponents to split up. If you hurry up, you should eliminate an opponent who walks towards stairs #1. Do not worry though if you can't make it, because you can deal with him later. Turn left and go to the end of corridor, reaching a terrorist patrolling this level. He should stand at the railing #2 and this is a perfect moment to get rid of him but do it unnoticed - there are his buddies under you.
Return now to the meeting room you've seen earlier (Meeting Room) and explore it carefully. You'll find an e-book and a newspaper there, plus a PDA with a password saved there.
You can reach lower level in two main ways. I do not recommend using stairs #1, because you could be seen. A much better way is to look around in the southern room - you'll find there an air vent entrance #2. It leads to men's room.
Note - the following description refers to a situation where all terrorists are alive. If you've killed first of them previously, one problem is already fixed.
Exit the toilet and focus on eliminating two terrorists walking around lower office room. It is good to kill the guy on a right first #1 and then deal with enemy to the left #2. In both cases you have to focus on remaining unnoticed and after eliminating opponents pulling away their bodies to some safe place (to the office room or under the stairs).
Now stun two left enemies who are coming to different computer terminals #1 #2. After securing the area, be sure to examine terrorists' bodies. You'll get three PDAs with access password to terminals.