He's not going to die, this whole incident will change Marcus way of thinking and and we see Gallen for what he is.
omg...i just saw episode 18...Marcus very poor thing! no wonder he'll turn bad later! he want back all his pride!! can't wait for episode 19!!!
Marcus got ill-treated by the bad guys when kidnapped, his thing not working well, wets his pants infront of his wife, wets the bed at night...lose all pride and face, surely something will trigger his mind to become evil.