It seems crazy to say that oneself would kill in the name of Christ.
It seems crazier to say that oneself would not kill to protect the ones one loves because they risk being killed in the name of Christ.
When He said "You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’ But I say to you, do not resist the evildoer. But whoever strikes you on the right cheek, turn the other to him as well." (Mt 5:38-39), he was referring to insults; not lethal attacks. Think about exactly what He said: "whoever strikes you on the right cheek...". Picture such a blow being delivered. How is it that one can be struck on the right side of the face when the attacker is most often right handed? A punch, thrown with the right hand, would land on the left side of the face. A backhanded strike, however, would hit the right side of the face. When the desire is to insult someone, a backhanded strike is used. The Lord is not referring to an attempt to do physical injury.
Later, the Lord advises to the disciples to arm themselves, selling their cloaks if need be. "Then Jesus said to them, “When I sent you out with no money bag, or traveler’s bag, or sandals, you didn't lack anything, did you?” They replied, “Nothing.” He said to them, “But now, the one who has a money bag must take it, and likewise a traveler’s bag too. And the one who has no sword must sell his cloak and buy one. For I tell you that this scripture must be fulfilled in me, ‘And he was counted with the transgressors.’ For what is written about me is being fulfilled.” So they said, “Look, Lord, here are two swords.” Then he told them, “It is enough.” (Lk 22:35-38) A sword is a lethal weapon. Clearly He is teaching us that a lethal attack (as opposed to a backhanded slap to the cheek) may be repelled with lethal force.
Christians are under no blanket obligation to be murdered. A particular Christian may be called to martyrdom, but that does not mean that all Christians are so called.