Walkthrough:Disco Demolitions
"Disco Demolitions" was a job for Bentley in "The Black Chateau" of Sly 2: Band of Thieves. This is Bentley's first job and serves as a tutorial.
Objective
Bomb all four support columns to the disco ball to drop it.
Walkthrough
Upon reaching the mission marker, Bentley will enter the door that Neyla led you to during "Moonlight Rendezvous." Once inside, Sly will give you a tutorial on how to use Bentley's bombs. To destroy the wall of lasers, press 
to place a bomb on the computer next to it. Make sure you stay clear of the explosion though, as they can hurt Bentley as well.
Once the lasers are gone, go forward, and you will spot a flashlight guard blocking the corridor. Here, Sly will give you a tutorial on how to use Bentley's sleep darts. Open his binocucom with 
, aim it at the guard and fire a tranquilizing dart with 
to put him to sleep. While he is asleep, quickly place a bomb next to him and move back before it blows. Next, place another explosive on the nearby wall of lasers to deactivate them. You will now enter the disco room.
The first pillar you must destroy is directly to the left of you. Jump down and place an explosive to destroy it. Run up the ramp to the left and stop at the top, where you will see another guard. Put him to sleep and bomb him. The next pillar is directly beside the door, so plant another explosive and proceed. Take out the third guard, and run across to destroy the third pillar. This will likely alert the final guard. Fire a dart at him before he attacks, and then continue on as usual. The fourth and final pillar is straight ahead. After destroying it, the disco ball will become loose and plummet to the ground, successfully ending the mission.