It is not the Contractors responsibility.
Does the Contractor tell him go to sealine on holidays?
Any Contractor will never say so...
It is his companions responsibility, if nobody ask this man to go sealine, he is still alive. So Contractor will not be punished by this tragedy, this is his will, even he knows how to swim or better far than swimmer.... or maybe he is drunk of alcohol, so he is thinking he is superman... that's it and that is life... His companions involvement must be investigated....