The subject KILLER part 4: the source of fire

The Fire Cube manufacturing line.

The control room.

Part four of The subject KILLER series, "the source of fire" begins in the corridor the player was left in at the end of "name of turrets". The floor opens underneath the player, dropping them down onto a catwalk next to a door labelled "Fire Cube Manufacturing". Fire Cube Manufacturing turns out to be a long conveyor belt transporting many Fire Cubes between two furnaces.

On the far right of the large room (from the perspective of the entrance door) the player will pass by a box and be prompted to pick up the Dual Portal Device, finally allowing them to place both portals. On the far left side of the room, the player can press a button to open a door leading to a staircase. This door does not fully open, forcing the player to retrieve the dual portal device to proceed.

Several floors up this staircase, the stairs become broken and mangled, forcing the player to place a portal in the open door on the other side to reach the control room.

In this control room, the player will encounter Wheatley again. He delivers some dialogue and leaves, with the player being prompted to push a button which opens a door at the far right side of the main room. This door gives the player access to an elevator that takes the player very far down.

After exiting the elevator, the player has to portal under a door that has been propped open with PC Cases. The player then proceeds though the linear office area until they reach a closed door labelled "Elevator to surface".

The player has to enter one of the rooms along the corridor and hit the override switch to open it.

The player then passes through a Material Emancipation Grid and into a rickety old elevator. The elevator slowly rises as the Announcer states that a powerup has been initiated. The map then ends.

## Secrets

### Sneak Peek

On the lowest level of the staircase leading up to the control room, there is a vent on the far wall. The player can portal through this vent to end up in a hidden Rat Man den containing an old style Companion Cube and an old style Weighted Storage Cube.

Entering this room will cause the text "Achievement Complete! - Sneak Peek" to appear.

### Transmission

On the far right side of the room, near the box were the player acquires the dual portal device, a Radio can be found. Taking this radio to the hidden Rattmann den and placing it near the door causes static to come through the radio and the misspelled text "Achievement Complete! - Trnsmission" to appear.

### Good Old Best Friends

If the player takes the Companion Cube from the Rattman den all the way to the first elevator, the text "Achievement Complete! - Good Old Best Friends" will appear.

### As seen in Half-life 2: Episode 2

In the area where the player has to portal under a propped open door, a CD can be found nearby. If this disc is taken to the end of the corridor, it can be placed inside a projector in one of the offices. This will cause the projector to display several slides of the Borealis, including photographs and blueprints, before displaying the code "835927".

### Friend Killer

If the player carries the Companion Cube from the Rattmann Den to the Material Emancipation Grid right before the old elevator and proceeds to emancipate it, the text "Achievement Complete! - Friend Killer" will appear.

## Notes

* It is possible to use the Weighted Storage Cube and Companion Cube from the Rattmann Den and a chair from the control room to stack up a makeshift staircase on the computers on the far right side of the room to make it over the railing and onto the Fire Cube conveyor belt. This allows the player to acquire infinite Fire Cubes, and is likely an unintentional glitch. Going into the furnace does not hurt the player.