At one point, a character tries to catch a helicopter pilot's attention by making the sun flash in the blade of a knife, and we see the effect close up.
Three people die; two of them (a woman and a man) we don't know at all, and the third (a man) is a arguably a secondary character. All three killed by the shark.
Honestly, the comment about the male actor having early onset dementia is just realllllly bad acting. Like, this guy is a horrible actor. Dementia and Alzheimer’s are not mentioned.