Deep Blue Sea

In a remote underwater facility, doctors Susan McCallister and Jim Whitlock are doing research on mako sharks to help in the re-activation of dormant human brain cells like those found in Alzheimer's disease patients. After one of the sharks escapes the facility and attempts to attack a boat full of young adults, financial backers send corporate executive Russell Franklin to investigate the facility. Susan and Jim prove their research is working by testing a certain protein complex that was removed from the brain tissue of their largest shark, which bites off Jim's right arm upon awakening in the laboratory. Brenda Kerns, the tower's operator, calls a helicopter to evacuate Jim, but as he is being lifted, the cable jams and it causes Jim to fall into the shark pen. The largest shark grabs the stretcher and pulls the helicopter into the tower, killing Brenda and the pilots, as well as causing massive explosions that severely damage the facility.