I'm unable to resolve this question, kindly assist with the answer.

Question 5 [15] X takes his Rottweiler dog for a walk in the park. Y approaches X, hits him in the face and knocks him to the ground. Y pulls out a gun, points it to X's head and says he will kill X if he does not give him his cellphone, watch and money. X gives his dog the command to attack Y. The dog bites Y in his throat and kills him. Y's wife institutes a claim for damages against X. You are X's attorney. Advice X on a relevant defence in protecting his legally recognised interest with reference to relevant case law