In the Belly of the Beast

In the Belly of the Beast is the second mission in Deus Ex: Human Revolution - The Missing Link.

Your mission here is to get to the interrogation wing, entrance to which is on the top level of the prison block. The wing itself is unguarded but the high levels of the detention camp are.

Second level is guarded by two security bots on patrol as well as two separate controlled laser grids. To eliminate them you can choose several tactics: Third level holds two Typhoon Turrets that should be avoided. They are activated by crossing their laser sensors, so timing the movements helps avoid them easily. You can destroy them as well (an EMP grenade or several shots from heavy weaponry will do) but for this no XP is awarded.
 * Brute force: EMP grenades, explosives or heavy weaponry are recommended. A rocket launcher acquired from Garvin Quinn's side quest is of great help. This is the hardest way of getting Ghost XP bonus.
 * Stealth action: the first level of the facility has three explosive barrels. Throwing them at bots and quickly hiding afterwards (or throwing them from the lower levels) can with some luck disable them. You won't get XP for destroying them this way, but it can help in getting Ghost XP bonus.
 * Stealth: open cameras on different levels have breakable doors that can be shot through, destroyed with Punch Through Walls aug or with explosives (explosive barrels, throwing crates, frag grenades etc). These ways lead to vertical ventilation shafts that can be traversed with high jumps aug. 2nd floor also has pockets where one can hide from patrolling bots. However the bots make hacking laser grids difficult, so cloaking is advised. Another option is to move the freely available crates into the way of the bots. Find the pinch points near where the lasers are (where the bot can't maneuver around an obstacle) and put a crate there. The bot will turn around, giving you enough time to finish your hacks.
 * Factory Zero stealth: when you go up, as soon as the bot there starts to move away from you, follow it as closely as you can. You will get through the laser grid as the bot temporarily turns it off to pass through. Then, hide in the open camera, allowing the bot to turn around and to go back past your camera. Then just waltz to the stairs leading up. When going back down from the third level, do the same thing, but it's important to take the left turn to follow the bot because only that side has two open cameras - one before and another after the laser grid. The other side only has one camera before the grid, so you got nowhere to hide once you cross it. Obviously, it's not as important when going down because the camera before the grid will be after the grid then.
 * Hacking: lvl 4 security terminal inside the guard tower in center of the Prison Block can disable bots (with proper hacking augmentations, or the password from one of the guards on the ground floor).

Returning to the main part of Belltower base at this point seems to add more guards (apparently Burke's commands were not just words). However all the security systems the player has already disabled (cameras, turrets, laser grids etc) remain offline. A thorough approach beforehand saves a lot of time and makes the mission easier.

Burke's office can be reached through the door (high security, lvl 1 lock) or ventilation duct (little to no security, lvl 3 lock). If Jensen has Social Augment and used it successfully when meeting Keitner, he will know the codes for the front door.

Quinn can be reached through the elevator (two more guards) or a ventilation shaft.