I have done up and down the room with the pink flashing platforms off the waterfall/weeping guy node. I can only find the door at the very top. It would be really helpful if someone could tell me where the other door is.
The other door is much closer to the bottom. To find it, start at the bottom door. First, go up to the top of the platform that you start on. Then use the flashing platforms to go up to a square block, from which you can jump to another square block. From that second square block you can jump to a wider platform. Rotate that platform until you see a door. That is the door you are looking for.