(2) Peaceful option: Getting inside the plant Deus Ex: HR Guide
Last update: 11 May 2016
Map legend: 1 - Main entrance to the plant; 2 - A road leading on the top of containers (to the air vent).
Lean out from a corner and quietly get rid of the first guard, preferably immediately, and not only when he will leave this place. I recommend using the option to stun enemies, activated with Q button by default (Jensen must be close to the attacked a person of course). The advantage of this is that the enemies have no chance to defend themselves against it. You do not need to waste your ammunition too, but it is required to regeneration a battery visible in the upper left corner. After a successful action, consider pulling the terrorist corpse near the ladder. Other opponents should not get here, but I'd better not risk. Think also about searching an opponent's corpse after each action. This particular one will have with him a PDA with a saved message beside other things.
There are three more terrorists near the entrance to the plant. If you want to kill them quietly, I suggest starting with one closest to you #1. However an attack must be made when other opponents are looking or going in other direction. Pull the terrorist's corpse to some isolated place. Now open the left gate #2 - you'll find stun gun ammo.
Jump on crates until you'll get into small tunnel #1. Go outside carefully, hiding behind new covers and waiting for the second opponent #2 to show up. Stun him when third terrorist seen in the distance will go away or watch in other direction.
Make sure to hide second opponent's corpse at least behind the crates #1. Now you have to eliminate only one enemy. Approach him, after he goes to the main entrance to the plant #2.
If you do not want to attack the opponents or you've already dealt with them, look for some kind of pyramid made of containers and crates, located north from the main entrance to the plant (screen above). Start climbing. Once on top, use the ladder.
Do not worry about electrical field on the ground and go to a crate to the right #1. Take it and put it on the side. You'll see a narrow passage which can be used. Go inside and get to the fuse box #2. After interacting with it, an electrical field will disappear.
Now you can continue your walk. After few moments you'll find an entrance to the air vent #1. Open it and get inside. The only possible way will lead you to the warehouse. Jump down on the big crate under you #2 and save the game.
Reward: 200 experience points + 500 experience points for staying undetected.