I'm currently completely stuck at this. I already solved it and opened the main entrance to Hollow Bastion, but I figured there's another chest down here that I can't seem to reach (can see it from entering another side entrance to the water ways). Now I also figured there are 2 switches don't need to be pressed for reaching the gate-switch.
Pretty sure these must be related to reaching that chest (since it's blocked by gates), but I'm unable to find any way to these two switches.
Looking into some FAQs also didn't help. Would somebody know anything about this chest and these switches? The chest is placed on a small platform sticking out of the wall in the upper level of the waterways.
I'm absolutely certain I've never frozen a water bubble to get anywhere, and yet I'm also absolutely certain that I haven't missed anything in this game. So either there's another way... or I've missed something and never realised.
Gum-Gum Gummi Ship: Blueprint Active! Straw Hat Pirates need a new Merry Go, c'mere Sora! Lend us your spacecraft!
You can go back the way you came to where the light switches are. Have Beast in your party and Call in the antechamber to have him break a wall. You may already have done this.
The other way back is using the lifts. In the first area is a lift that looks like it only goes to the top where you can Gravity down a chest. But if you proceed in the lift hallway a bit, on the other side is a useless looking switch. Examine it, and it will say something like "lower level". The lift will now take you to the waterway. Fair warning, the enemies are tough there. Beat up the enemies and at the end of the hallway is a platform marked Dungeon. That'll take you to the same place.
Ryu23456, when hunting for a chest ElectroSpecter's walkthrough is where to look for how-to info. Only one chest is missed in that guide, and it's not a visible chest (and contains only a Camping Set).
SinisterSandman, freezing the lower of the two bubbles beside the Waterway save point lets you reach a chest that's overhead, in the rafters. The chest contains a Flare-G gummi block. This is the chest that may have been seen from the Waterway area reached by extending and hopping across the two big platforms in Base Level. There's usually no other way to reach this chest, except perhaps very late in a game when High Jump can reach great heights.
Guides & other contributions: http://www.esque.com/slr/gamefaqs/ FFX, FFXII, KH, KH Re:CoM, KH2, Okage: Shadow King