According to YouTube user CalSmack the nurse shark seen in the video had been hooked on a fishing line, which still had a weight attached to it. The line had become entangled in the surrounding coral preventing the shark from moving. Having nothing to cut the line with but his room key, the snorkeler seen in the video managed to sever line “as close to the shark’s mouth” as he could allowing the nurse shark to swim away freely. Kudos to the snorkeler for his efforts!