Weird "door" in the E zone

Not sure if anyone's active enough to see posts here anymore, but I've been playing Uurnog recently and loving it, but I've found something I can't make sense of.

There's a room inside the E zone that has a blocked up doorway that seemingly has no purpose, and yet it looks awfully suspicious.
I've tried everything I could think of, using the blue and red orbs (which on a side note I still haven't found any use for), using a bomb, exploding a heart with the heal gun, using the gold key.
Is there a way to open it, or is it just taunting scenery?

Just keep progressing through the game, and eventually something in that room will change. You'll know when.

Regarding the blue and red orbs, have you noticed them repeatedly flash and beep at times? (And have you noticed the red orb flicker green?)

Just keep progressing through the game, and eventually something in that room will change. You'll know when.

Spoiler: To be less vague... (click to show/hide)

When you get the train job ending, the corresponding cutscene will show you that exact room but with the doorway covered by blue boxes. There's a door behind those boxes.

Regarding the blue and red orbs, have you noticed them repeatedly flash and beep at times? (And have you noticed the red orb flicker green?)

Yes, thank you very much. I actually just came here to update the thread because I figured all of those things out coincidentally. I had held off on the endings because I was trying to figure out as much as I could about the secrets and stuff beforehand, which turned out to not be very productive. And I did notice the green flashing of the Red Orb, which I couldn't make sense of at first, but now I found its use! Love uncovering things in this game.