did ll cool j die in the end of deep blue sea

No. In the released film, LL Cool J (Preacher) and Thomas Jane (Carter Blake) made it to the surface.

However, in the original version of the film, Saffron Burrows (Dr. Susan McCallister) survived and, even worse, was the hero of the film.

The original ending stayed in place until some test audiences saw the flick and absolutely hated it. So they did a quick reshoot less than a month before release and had her get devoured by a CGI shark — and the crowd went wild.

Director Renny Harlin talked about the changes in an interview with Crave Online, after being asked by a reporter who saw the original cut in a test screening:

Yeah, it was one of those great surprises where we thought, okay, we hope it works. At the test screening, as you might remember, the audience was really with the movie and when Sam Jackson gets eaten, the audience was screaming and laughing and we thought, okay, it’s a home run. When it came to the last seven minutes of the film, all of a sudden it just fell flat like a pancake and people kind of hated it. We were like, what the hell happened?

It just shows how sometimes you can be clueless and you’re so deep in the project that you can’t read the audience’s mind. Basically what had happened was that the audience felt so deeply that the scientist character, the woman who was behind the whole experiment with the sharks, that it was all her fault. In their minds, she was the bad guy and in our minds, she was the heroine and we thought saving her was the key. Basically, we had test cards that said, “Kill the bitch.” It was an amazing revelation.

I remember us all sitting down and going, “Holy shit, we are in trouble. How do we fix this?” It was my idea, I said, “Okay, we don’t have time for a big reshoot but I have an idea. When she falls in the water, what if she doesn’t survive. She gets eaten by the sharks and L.L. Cool J is the hero. Everybody likes him, and Thomas Jane.” We did a one-day reshoot at Universal Studios’ tank and it was a really simple shoot we did in order to change the ending of it. We did some CG work on the sharks and stuff like that, but it was a super fast fix and it saved the movie because the audience got what they wanted. It just goes to show that no matter how smart we think we are, it’s the audience who will tell us how it’s really supposed to be.

Monday, September 18 2017
Source: http://www.syfy.com/syfywire/deep-blue-seas-original-ending-and-why-audiences-hated-it-finally-revealed