The sharks

true. sharks don't behave that way irl. they dislike humans. not enough fat to sustain them like a seal. Kate was killed by the shark because she was bleeding and because it made the situation more dramatic. They made the sharks ultra aggressive and larger than normal for the same reason. they kind of ignored the fact that Lisa's hand was cut because of Javier's speargun going off as well. Extra blood would attract more sharks.

Great Whites are rarely found in waters near Cancun.

Bull Sharks are the most dangerous species (man-eaters) found consistently in those waters.

Also, Great Whites don't tend to congregate in "packs" of three or more like in the movie. Only in feeding grounds where seals are found in abundance.

I agree that the sharks didn’t act like real sharks would, but I think that’s what makes it scary. I’m old enough to have seen JAWS in the theater back in ‘75, and that shark took on almost supernatural tones. Not only was it bigger and stronger than other sharks, but it also seemed to show intelligence. It was consistently one or two steps ahead of the experts, and that made it even more terrifying. Without one word of dialogue, the shark was a fully-realized character.

Back to 47 Meters Down and the sharks, they’re nowhere near as terrifying as the shark in JAWS, but the legacy of that movie casts a wide spell over this one, and it’s for the better. The best scenes are when we don’t see the sharks, just the dark, murky water. Brrrr.