stumped

in reading Bonhoeffer's The Cost of Discipleship, I'm actually surprised that I've made it thru 12 chapters without getting all mentally twisted up. He writes very well, he's a really smart man and I have to read some stuff 2 or 3 times. Kinda like Tozer. Mmmmm, Tozer.
anyway, so the chapter I just finished was about revenge, and it quoted from the obvious text of Mt 5:38-42 - turn the other cheek, give up your cloak and your coat, go the extra mile, etc, etc. "Don't resist evil", basically. There was a mention of this being just an extension of the Beatitudes, because it's Jesus's followers showing meekness, etc, which I get. And I understand the idea of overcoming evil with good, I love the part in Romans where Paul talks about doing good to those that persecute you because then it's like heaping hot coals on their heads. That's kinda sweet. He also mentions toward the end of the chapter that it's really Christ's triumph on Calvary that allows his disciples to act in the same way - it's the ultimate example of not resisting evil and coming out on top. You have to suffer along the way, but in the end it's worth it. I get that, it's cool, but what I'm not really understanding is the idea of not resisting any sort of evil at all, which seems to be understood.
I remember quite clearly the pastor at my mom's church talking about the same passage of scripture, about turning the other cheek, and what he said made perfect sense at the time. It was basically - if someone's attacking you because you're a Christian, then yes, you turn the other cheek and show them love and kindness. But if someone's breaking into your house and they don't know you and don't care about your ideological beliefs, then you have a responsibility to protect your family and you'd better find yourself a baseball bat. But then there's Dietrich talking about not resisting any form of evil at all, because that only adds fuel to the fire.
I guess it makes sense if you look at it as fighting fire with fire, or evil with evil. If I fight back and end up beating someone to a pulp, then I have done something evil myself. But then this flies in the face of common sense, not to mention most people's instincts. If someone is threatening your life, your instincts will kick in to help you defend yourself. But then, the argument is made that if you are following Jesus, you've given all your rights up to him, even the rights to your own life. I can't really argue with that, it's what Jesus himself did, but it seems so senseless to want your followers to just roll over and take every beating that comes their way. I don't mind the idea of the little verbal beatings or maybe even being falsely accused of something or even to the point of being mugged in a back alley, whatever. But if there was some point when I was dragged into the bushes at a park by some stranger, I would have a really hard time with the idea of just passively letting whatever evil happen that this guy has on his mind. Is it really evil if it's self-preservation?