To whomever finds this: Sudra is miraculous - the fact that I've been healed attests to that - but it is too dangerous to bring this technology back to Earth. Whatever happened here was catastrophic, the ramifications extending to everyone.
We are going upstream - to the Filter, or whatever lies beyond - for answers.
About the Note
This is the only brown note. It is written in English, and is believed to have been made by the prime Trace hundreds of years ago when he first arrived in Sudra. It is located near an abandoned wheelchair. This note suggests that at the time of writing, the prime Trace had already used the Rebirth Chambers and healed himself of all injuries from the lab explosion.
The "we" in the note is ambiguous. It most likely refers to Trace's colleague Hammond, who may have accompanied him to Sudra. This would make sense because the prime Trace had been blind and wheelchair-bound, and would have had difficulty making the journey alone. Another possibility is that at this point, Trace had already created multiple clones of himself and the "we" refers to those clones.
This is Note 02.
It is in a room right above the Rebirth Chamber you wake up from at the start of the game. Use the Laser Drill on the top of the wall just left of where you picked up the Axiom Disruptor and enter the upper door.