I know I'm late here, but I want to offer a similar experience this past week from the Red Sea as well (BDE route).
I was buddied up with another diver who was a bit heavy on air but generally good at conserving it during 3 easy check dives, and he added a 15L tank. On the second day we were doing Elphinstone and they changed the group we were in to one with a different guide than we had for the check dives. We were told the plan for Elphinstone was to follow the guide to 30m on a drift from north to south, look for hammerheads, and then rise up explore the southern plateau. He would check our air at intervals so we could plan to surface as a group with him deploying his DSMB and us doing the whole two-by-two zodiac pickup while looking out for white tips.
At the start of the dive, the guide takes off into the blue with his camera and we're all struggling to keep up. We're down at 30m for way too long IMO. My buddy lets me know when he's at half tank and so we attempt multiple times to signal the guide (sounds, waves, trying to catch up to grab his fins, whatever), as we were told to let him know when at half tank so he can plan the gradual ascent. The guide didn't turn around a single time during this dive. So my buddy and I start shallowing up. But within 5 mins my buddy signals he's at 60 bar, we're at 20m. Ok, clearly we need to start a safety stop fairly soon. I try again to signal the guide; I have thrown out the idea of trying to catch up with him because I don't need my buddy to burn more air during the swim, luckily someone else in the group hears my banging and gets the guide's attention. I point to my buddy and signal 60 bar. The guide signals that we (just my buddy and I) should do a safety stop. The briefing said to deploy a DSMB for a safety stop so I start to get mine ready and I deploy it while the guide continues to drift with the rest of the group. I see the zodiac come around so we hang and do our 3 mins but then suddenly two others from the group decide to join my DSMB for the safety stop. I point to my buddy that he should go up on the zodiac as he's low on air, I'll hang with my DSMB so the others can complete their stop. Instead, everyone except me tries to surface at once and they all surface swim for the zodiac instead of surfacing underneath it one by one. Suddenly, the guide is next to me admonishing *me* for their behavior, and once we all get back onboard he yells at me for deploying my DoSMB, tells me we should have waited for him and that we can "always buddy breathe, better to follow the guide."
I also like you spent a few days ruminating on how I could have done it better. But sometimes we have to make judgment calls when we're left to our own devices by guides more interested in photos/whatever instead of being more attentive. I don't mind guides who have a plan and dive it, and I don't mind unguided diving either, but I do bloody mind guides who don't dive the plan (including being attentive to their group) and then blame the group for having to make decisions on the fly.