If a close friend or family member were in danger I think it would be easy for anyone to lose control. I am a calm, laid back sort of dude, but nothing sets me off like someone messing with my friends or family. I don't know what I would be capable of if I were put in those situations with her powers.
I felt it was very much in character and I liked the way she was portrayed.

I assume the question is rhetorical, since I am not a Christian. Nor is there anything in my original post to suggest a religious frame of reference.

Why are Christians so scared of everything? Everybody dies. everybody

Nailed it.

So you expect a child whos emotionally unstable to use rational thinking when she's angry and afraid? When she's out in the real world with her unhuman powers, not knowing what to do with herself. Good luck with that.

Whilst it wasn't essential for them to die it really did impact on the plot and characters. We got to see Papa get what he wanted, we got to see a child not totally in control of her powers lash out in self defense.
When she realises what she's done Eleven is utterly mortified with herself and shrinks from Papa's hug. We learn so much about how much of a psycho Papa is and it sets up the later scene where Eleven's convinced she's the monster.
And remember these may be "orderlies" but they're manhandling a 12 year old girl to a solitary confinement cell. Now who's the Monster, the Demogorgon? Sure it's a threat but it's only eating or procreating, Brenner and the others at the lab have stolen a baby girl and raised her in isolation forcing her to perform acts like killing a cat. So I'm not that upset by any harm that befalls them.

It's true that Eleven is something of a homicidal maniac with a mercilessly short fuse. But as well as being cat friendly she does occasionally show remorse (for opening the Gate for instance) so there is hope for her.
To answer your question though wasn't Eleven being trained to be a weapon? Perhaps she had been conditioned to have a hostile temperament like any fit-for-purpose attack dog
The Players of The Game are the scum of the earth.

Eleven wasn't thinking when she killed the orderlies, just lashing out in fear. Brenner set up that situation to push her into fighting back. And he seemed pleasantly surprised by the result, like it exceeded his expectations. You can't really feel sorry for the bully who got Mike to jump by threatening to carve up Dustin's jaw with his knife and forcibly extract what teeth he had. Maybe he's incredibly stupid and thought Mike would simply get banged up and wet, or maybe he's a budding sociopath who
wanted
Mike to die. Either way he deserved to be taught a lesson. The agents at the end she killed on purpose. She didn't technically
need
to crush their skulls, but she knows what kind of people they are and the threat they pose to her friends - plus with that particular woman in the lead I'm sure payback for poor Benny was on her mind too.

Lucas was a friend and got thrown around. The bully deserved worse. That whole scene was kind of OTT what with the bully demanding Mike jump off a cliff or slit Dustin's throat. Breaking an arm wasn't all that bad in the context.
Agreed. That whole scene was over the top.

That's no flaw. There's nothing wrong with killing in self defense, but she's not going to kill a kitty just to please Evil Papa. Plus, it was more of an instinctual reaction, not conscious thought.
Lucas was a friend and got thrown around. The bully deserved worse. That whole scene was kind of OTT what with the bully demanding Mike jump off a cliff or slit Dustin's throat. Breaking an arm wasn't all that bad in the context.

Daniel Plainview is one of my favorite characters of all time. I could watch that movie all the time.
Not me. The flaw that stood out the most for that movie is Plainview is a vile and despicable character.

One of these days I'm going to cut you into little pieces.

Daniel Plainview is one of my favorite characters of all time. I could watch that movie all the time.

Understood, but that's not really a flaw. That's just you not liking a character's behavior pattern.
I absolutely hate There Will Be Blood because I cannot stand the character Daniel Plainview, such a vile and despicable character. But I do not see it as a flaw of the film, it was a great performance by Daniel Day Lewis, but I despise the character. That doesn't make it a flaw.

One of these days I'm going to cut you into little pieces.