[ when cloud says that, hope immediately tries to open the door again... only to find that, unlike the last room, this one stays firmly shut. hm. ]

Looks like there's no turning back now.

[ turning back around to face the park, he starts to once again take in their surroundings, looking for a hint on what they're supposed to accomplish or experience here. ]

I get the feeling these rooms are related in some way to the previous games. The Prism—I think that's what this one is called—seemed to place heavy emphasis on colors... so this might be representative of its antithesis.