The door isn't the only fragile thing in this chamber. As always, breaking the puzzle first requires grabbing the cube.
What do I need to do?
Throw the cube on top of the platform that takes you up to the elevator. After a few seconds, unique dialogue will play and the door at the end of the hall will be forced open.
What is the unique dialogue?
"Despite the best efforts of the Enrichment Center staff to ensure the safe performance of all authorized activities, you have managed to ensnare yourself permanently inside this room. A complimentary escape hatch will open in three... Two... One."
Thanks to YouTuber Marblr; I found this softlock through their excellent "Every Softlock in Portal" video!
Guide help
This is the low-spoiler guide for "Breaking the puzzle" puzzle in Portal. Unlike in normal walkthrough, you get gradual hints on how to solve the puzzle. Click the big button below to see your first hint. If the hint contains a spoiler, you will be warned about it before clicking.
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