[MENTION=13911]Tomb1[/MENTION] - We can certainly agree to disagree since that's kind of our thing, but I just thought I'd expand on my reasoning here.
Eli and Carnegie are not cut of the same cloth but rather a juxtaposition of power via good vs evil. Carnegie is looking for power and will ruthlessly take out anyone who gets in the way, including Solara's mother whom appears to be his partner via slavery, essentially. Eli is certainly brutal, but never without justification (keyword: justice) and never out of lust but rather as the judge, jury, and executioner.
This scene contrasts the two in terms of their motivations. It is clear that Eli is digging for motives from Carnegie and getting a feel for his surroundings in order to gauge what his next move should be. He is strategizing based on analysis of Carnegie's character/goodness or evilness (and of course awareness of his surroundings). Carnegie discusses the power of possessing the Bible under the guise of righteousness so as to appeal to Eli's code of ethics. Eli responds to Carnegie in the most sincere of ways but isn't a fool because he knows that if Carnegie possessed the Bible, he'd only use it for evil and power. In fact, I think the entire purpose of this scene is to contrast both character's motives. Let's not forget that this entire movie is based in Christianity and revolves around Good vs. Evil.
I think it was with great intention that both characters were similar in their power yet so different in their motives and morals.
This is ruthless aggression rooted in lust:
This next scene is righteous anger rooted in principle. Eli even defends himself against accusations of pushing the cat intentionally, which an 8 would not feel a need to do, especially in the tone in which Eli speaks. Furthermore, he makes it clear he doesn't "want any trouble" to give the man a way out, which is a repeated theme in the movie, and then has a visible "ah, fuck" reaction when the guy dies, which he didn't intend. The group fight scene is out of necessity/self-defense, and again dripping in biblical code of conduct. He even stops when Solara yells "Stop!":
I was unable to find this scene, but toward the beginning, Solara is sent to Eli's room to sexually satisfy him. Eli responds immediately by walking quietly to the door and opening it to show her the way out. This is a bit of a literal example but i think valuable nonetheless as it shows self-discipline > lust. He lets her stay the night without sex only after she tells him that Carnegie will hurt her mother if she doesn't.
As far as Socionics/MB type goes, I see more wiggle room there, but also... that's not really my jam so much as Enneagram and internal motivations, so I'm not really invested in defending a particular type for him there, but I do think he uses Se, Ni, Te, and Fi in some order, and is an obvious thinker.