I guess next limbs will come off and flipside will go all monty python black knight on us.
Bit late for that. Both Mr. I-Beam and Yo-yo girl lost an arm already.
As for the "murder is wrong" thing. Murder is ALWAYS wrong. No exceptions. The death penalty is NOT murder. It is the taking of a guilty criminal's life as punishment for a specific crime, and all the way back to the code of Hamurabi, rape is an offense that warrants the death penalty. Even the second commandment specifically allows for the death penalty. "He who sheds innocent blood shall be slain by human hands."
The death penalty requires a little something called "due process." That is, bringing forth evidence, witnesses and delivering judgement from a higher power. A man running up and killing someone because he THINKS (or "knows") a guy raped his daughter would be homicide, a lesser form of murder, and could itself be punishable by death.
Self-defense is not murder. Someone breaks into your house, he's not there to deliver a check from Ed Mc Mahon. He's there to steal, KILL, and destroy. You still don't get to chase him down and kill him if he flees, however. Someone comes at you with a weapon, and you fight back, resulting in his death, it's not murder.
Soldiers killing enemy soldiers on the battlefield is not murder. It's war. And both armies are fighting to survive. Combatants firing rockets into a civilian dwelling, or deliberately targeting unarmed non-combatants IS murder.
Extremists running into a civilian establishment seeking to kill as many people as possible is not "holy." It's murder. Even if they try to "justify" it by claiming "provocation" afterwards, by pointing to a set of "laws" that isn't even written down. (The Koran does NOT say "go forth and kill everyone who utters the name mohammad, or dares draw a picture of his likeness," for example.)
As for Bern's options? She's already cut off his arm and left deep gashes in his chest, and he keeps coming! (Not to mention destroying his weapon.)
Also, remember her style is almost exclusively counter attacks. It is very difficult for her to do anything preemptive.
He's also extremely "proud," determined, and believes he has a license to kill, or die trying. Bern's in a really hard place right now, and I don't envy her for a moment.