Subject 234
Soon after slipping past a few big fans, you'll enter a tiny office. A door near the back of this office leads to test chamber 09's observation room, where you can see the file for Subject 234 (who, unlike subject 42, seems to be human - and approved for testing.)
The notes on the clipboard are too low-resolution to make out, but you can also see 'Subject ID 234' on the relaxation vault you wake up from in chamber 00.
Guide listing help
Unlike normal walkthroughs, in Nice Game Hints you can select just the puzzle you want hints for. Here are listed the puzzles for "Subject 234" in Portal. The guide you choose only contains information about that puzzle, reducing possible spoilers for other puzzles.
Hints written by Kieron West
Kieron West
Hi! I have written video game guides since 2018. Any money I make here will go towards improving my equipment so I can make the things you enjoy even better (and faster!)