Portal 2 Chapter 4 Test Chamber 21
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sp_a2_bts1.bsp Jail Break
This is the thirtieth level of the game, and the final part of Chapter 4. This level is set within a Test Chamber and the maintenance areas of the Aperture Science facility. This level advances the central plot, and does not contain any significant Portal-related challenges.
sp_a2_bts2.bsp Escape
Contents
Mechanics
- Heavy Duty Super-Colliding Super Button
- Weighted Storage Cube
- Hard Light Bridge
- Pedestal Button
- Vital Apparatus Vent
- Light Strip (blue, pink, white, behind-the-scenes)
Characters
Objective
- Escape GLaDOS' Test Shaft (Test Chamber 21)
Hazards
Walkthrough
Intended Chamber Solution
- Place a portal on the wall where the Hard Light Bridge ends and the other one on the left side of the exit.
- Go through the portal and push the Switch.
- Continue to walk to the cube.
- Put the cube on the button.
- Use the portal again to proceed to the chamber lock.
Actual Course of Action
Escaping (Part 1)
- Wait for Wheatley to open the wall and run to the Maintenance area.
- Run to the left and continue forwards.
- Turn right on just before the catwalk ends.
- Turn left and jump down. Continue by to the right up the stairs.
- Run forward as much as you can. Turn left and continue running.
- Jump down on the left side.
- Use the Bridge and run away from the Chamber until the Bridge disappears.
- Turn to the opposite direction and continue running.
Escaping (Part 2)
- Jump from the catwalk to the area between chambers and run forward until you get to the wall.
- Pick up the turret and knock over the turret behind it.
- Turn left and go behind the tube and knock over the third turret.
- Let go off the turret (make sure it gets knocked over).
- Open a portal on the wall near the third turret. Shoot the other portal behind the panels where the third turret is. Go through the portal.
- Run to the right and follow Wheatley until a turret is revealed on the left.
Sector Destruction
- Get rid of the turret by using a portal and continue following Wheatley. Enter the elevator at the end of the catwalk.
- Wait for the elevator to stop and go through the door.
Video walkthrough
Download demo files: 
Part 1 – Part 2
Related achievements
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SaBOTour Make a break for it |
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Good Listener Take GLaDOS' escape advice |
Trivia
- If you take too long to escape the test chamber, GLaDOS will fill the room with neurotoxin.
- If you fall for GLaDOS's attempt to trick you back into testing, she traps you and fills the room with neurotoxin.
- The music was remixed by the game Portal Roleplay: Remastered.
Music
An Accent Beyond by Aperture Science Psychoacoustics Laboratory [2:58] | Download | 
Play
Gallery
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Transcript
[ARRIVAL]
GLaDOS: I've got a surprise for you after this next test. Not a fake, tragic surprise like last time.
GLaDOS: A REAL suprise, with tragic consequences... ...and REAL confetti this time. The good stuff.
GLaDOS: Our last bag. Part of me's going to miss it - but at the end of the day - it was just taking up space.
[LIGHTS TURN OFF]
GLaDOS: What's going on?
GLaDOS: Who turned off the lights?
[PANELS]
Wheatley: Hey, buddy!
Wheatley: I'm speaking in an accent that is beyond her range of hearin'!
Wheatley: I know I'm early, but we have---
GLaDOS: Look, metal ball - I CAN hear you.
Wheatley: Run, I don't need to do the voice. RUN...
[WHEATLEY OPENS THE PANELS]
Wheatley: RUN!!!
Wheatley: Come on, come on!
Wheatley: Run! Come on - I'm closing the doors!
Wheatley: Run! Come on - I'm closing the doors!