...too bad I haven't recorded either CE or FR for rings yet. At least I still have this relic of the FR completion.
And fortunately I have a 32-emblem file that I used purely for ripping the "story preview" cutscenes, so that put me right at CC with a no-Air-Necklace file. There were a couple of upgrades I needed, so I got those, then I knocked out pink and blue in succession, in one video file
(70MB, 19 minutes long). To go with blue, I decided not just to get all rings with Knuckles, but with the other characters too. It turns out that the lightning shield (and Sonic's ring chain) requires Rouge's Mystic Melody, but not Eggman's...of course, if you don't have Eggman's, you're trapped in the tunnel! The only ways to get out are to restart the whole stage (which makes it for naught) or to die, and there's only one way to die in the tunnel. So of course that's shown.
As far as Knuckles, the one that actually counts, I ended up limiting myself to 2 air bubbles. 1 and probably even 0 are possible, but they would require a lot more splitting up of excursions into the Kool-Aid. As far as the end, you're probably well aware that death leaves 2.9 seconds for things to happen, and the screen starts fading here after 2.6. Of course on DC I have 11 fewer rings to find, including the Big ring, but if they were there they'd both be quite easy to get from this position.
Rouge ended up taking 2 tries (not including the intentional tank after the shrine), Knuckles took 2, and Sonic took 3. Biolizard took...a lot more than 3.