I have a little different spin on the same basic question. My wife and I took an advanced combative pistol course recently. We are very committed and evangelical Christians who actively live our faith the best we can. We love to shoot our pistols. Our course instructor was a very well respected personal defense firearms instructor, former LEO, FBI firearms instructor, etc. However, he used very profane language when talking about the bad guys, etc. I was squirming inside because I knew my wife was not comfortable with his choice of adjectives for the most part.
During our lunch break we were talking about the couse material, etc. and my wife made the statement that applies here. As Christians, we are prepared to die. There is no fear in death and so is going through the training to defend ourselves really necassary? She continued questioning whether she was mentally and spiritually prepared to take another life that certainly did not have that same security.
The weekend went on and the weeks have passed I assured her that the Lord would only use her as an instrument of destruction if he so chose, but she should be prepared to protect her life, the lives of our children, my life if necessary, and certainly the lives of any other innocents if need be.
A close friend of ours and also member of our church is an ATF agent was telling her that he would count it a privilidge to be used by the Lord to protect His children if need be but would never wish the threat on anyone.
I also reminded her of the lady who shot and killed that church sniper not too long ago, saving who knows how many church members.
I think the pastor's conflict with the turn the other cheek is maybe in the intent of the message. We are to love our enemies and return evil with kindness as an act of love to them. However, that is not possible if we are dead and is not a testimony to our faith unless we die for Christ. A carjacking or robbery is not about our faith. Therefore we are protecting ourselves and potentially others, both at the time and possibly the future by using our weapon. And yes, in that, we may lay our life down for another by engaging a threat. If we are successful in stopping them and are mortally wounded in the process, we won't know the lives we saved until the Lord reveals them to us in Heaven, if he chooses.
So, if you engage another with a weapon of you own, you'd better be prepared to die because your are now a much greater threat than if you turned the other cheek.
She has made the choice to carry concealled.