Payday: The Heist

You have to kill every thug in the Panic Room heist within 60 seconds. The timer starts as soon as you draw out your weapons. If you pass the blocking guards on the stairs that leads to third floor, you will automatically draw your weapons. You only need to kill the thugs that carry a gun so you can ignore the civilians and Chavez.

To get this trophy easily, you need four players. Each player can clean a floor. One player stays on the bottom floor and one player stands on the second floor while the two others wait at the stairs to the third floor. These two players will clean up the third and fourth floor. Then start killing as fast as you can. Don't forget to check the fire escape, the roof and the alley outside the building.

This trophy is possible to get in single-player mode with AI, but can be hard to pull off and is more luck based. Basically you want to run to a floor and check all the rooms. Quickly kill one or more thugs in the rooms but leave the thugs in the corridor. Then go to next floor and do the same. Hopefully your AI-controlled teammates will follow you and clean up the corridor as they go. If you are lucky enough and no enemies are spawned on the fire escape or the roof, you will get the trophy.