Click here to download Gel Velocity
Click here to download Gel Velocity
&
Click here to download Gel Velocity
Click here to download Gel Velocity
&
As you can see, there are a couple of issues to be addressed....
...and thanks for mentioning that I have to subscribe to my own map. That sounds like a case of user error waiting to happen.
EDIT: Wow, okay, really glad you submitted that. It seems obvious in retrospect, since it's something I did many times, but I thought the turret might actually kill.
Made a few other changes. Also, a bonus screenshot from a previous version (not part of the solution, and not particularly an interesting stunt):
This should give you an idea of how carefully I placed those light strips. 
They are a decent substitute for going into hammer and specifying the exact portalable area.
Edit: Le video.
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That was exactly how I hoped the first half would go, sicklebrick.
But seriously, my intention for part 2
||In part 2, about 42 seconds in sicklebrick makes the gel go back through the floor portal to hit the ceiling, and that's incredible. Not once is that floor button needed. In another world, that would be a Steam achievement of some sort.
My way was to use the button to angle the panel, and put one portal on the panel (while standing on the button) and one portal on the bottom of the far wall. The angle of the panel is enough that the gel will paint a bit of the floor under the grating. The player steps off the button, portals the now-lowered panel, and portals the new spot on the floor. Because the white gel is falling from the high ceiling, it has more than enough velocity to reach the low ceiling directly above the floor portal.
At this point, the player cannot enter an infinite fall because of the grating on the floor, but a gel blob can. sicklebrick demonstrates this part to the letter, putting the gel in an infinite fall before portaling the floor near the cube and paining a bit of ceiling. Then it's a simple matter of putting a portal up there, falling through it, and getting the cube.
That came out to be a lot of words.||
Well, okay, mostly as planned. No less awesome, though.
EDIT: And then I finally realized how I wanted to end the chamber.
Two extra challenges for you:
- You can use the chamber three solution in chamber two. Try it.- See if you can get blue gel here:

It's not that tricky, and there's no timing; you only need to place each portal once to get the gel from the dropper to that part of the wall.
There are a few ways to solve the new room, so feel free to share your solution.
Fun fact: there are no cube droppers on this map. They weren't necessary, and sometimes they would have even been in the way. But you don't need to worry. (If you've dropped a cube in goo, look around. You might have missed the complimentary escape hatch.)
Playthrough videos, bug reports (if you find any), comments, or lighting feedback are greatly appreciated. Anything, really.