These verses in Romans are referring to people who despise, persecute, and otherwise hate you for your faith, or people who are just plain mean. Think about it like this: Say I have a friend who says some unkind things about me because I like PC's better than Macs. This passage is saying that I am not to come up with even more colorful phrases to describe him, but instead I am to forgive him. This is the kind of enemy these passages are referring to.
However, think about the shooter in this story. He was there with the intention of taking lives. Now, I fully belive that God can handle a single man with a gun. And I believe that He did. He made sure that this security guard was there on the day that the shooter came; He provided protection for His church.
Now, you may say, "God could have taken care of the shooter; She was taking matters into her own hands instead of trusting God." Ok, then, think about this example; I'm driving across a bridge, and the car in front of me veers into the water. I'm not just going to think, "Oh, that's fine. God will just pop them right back out of the water." I'm going to stop and call for help! That is not taking matters into my own hands, it is saying, "God had me here for a reason today, and that was to help these people!" That is one of the absolute coolest things about God, that, even though He is more than capable of doing everything himself, He chooses to work through us!
As to contradictions, I challenge you to find even <b>one</b> contradiction that isn't taken out of context or a downright lie.
Very Best,
JP the Drummer