I don't want to pile on, but reading the (poorly written) report, she states that the DM pointing out the shark distracted them from buddying up.... But earlier in the report, she apparently left her husband as he had trouble descending, and waited for him below with the group. So really, they had already neglected to properly buddy up. And really, there is going to be a lot of sights during a dive. It's up to divers to maintain buddy contact despite all the distractions.
Also, I don't think a dive op is responsible for reminding folks about narcosis.
I suppose if I lost a loved one, I might try to cast about for blame. But I don't really see anything wrong about the dive op, except maybe the pulling of the "rip cord" for her, and who knows what that's accurately conveyed.
That struck me too. I've never heard of buddying up once underwater; if two people need to descend more slowly than the rest of the group, either they should be each other's buddies, or their buddies should wait for them. If that's accurately reported, it seems like failing on the part of the couple/buddies in question, but also the dive op for encouraging it.