I saw this picture, captioned, "Say cheese." Made me think the shark might say, "Guys head was crunchy." (Mask, snorkel, skull...)
That is pretty tame, @pearlselby. Some of the guys here jump in with large schools of large tiger sharks. In deeper water, with no tanks. And swim near the surface. Nuts!!
Sharks gotta eat... And, that is all they do; swim, eat and reproduce. In my youth, I would spear fish with a Hawaiian Sling off Ka'ena Point. Swimming with large predators like Tigers is kind of like playing headlight tag on a freeway or feeding Grizzly Bears by hand.
And they are out that side in good numbers. Big ones too! Guys regularly, as in practically daily, go out and swim with them. Play chicken with them. I dunno, I am not that brave. When spear fishing (I use a Hawaiian Sling too), if I see a shark near by, I will just get out of the water, especially if I caught something. And even if I didn't. Get out, make my way by land to a different spot and get back in at least one of two coves over. I know it's not that far. But I feel better that way. Give the man in the gray suit his space. And I carry a net bag for my catch. Nothing on my body. I don't mind giving up the bag, if I have to. Never had to yet... knock on wood.
I am pretty certain sharks can read the electronic signature of potential prey, and select the weak, sick, old, and injured on more than just a blood spoor. And perhaps they can even read the inattentive as ambush-worthy.. The same way, I think they recognize another hunting predator, and rate them low as potential prey because the kill-cost might be too high.