The MC isn't afraid of a romantic commitment, he is incapable of it, because he still can't let go of Zaina. He even says as much when he and Alistar step outside to discuss Vi and Ines staying with them for good. The MC can't even have someone say her name out loud without falling apart, so that needs to be resolved first for the MC to enter a new commited relationship; he can't start something new with a Ghost still hovering over him.
As for Els, I always knew that something is seriously wrong with her, just not what exactly. Part 6 helped a lot in honing in on what exactly that is though.
We get the first "warning" when Els and the MC go to the movies and the MC has a conversation with Zaina, who is obviously dead, so he is really talking to his subconscious.
"She's perfect, or that's what she wants people to see." and then the one word that kinda sets the tone as far as Els is concerned "Dangerous.". The MC with his military background calling her dangerous always stuck with me, but I never could put it together.
I thought we need to know what trauma Els has suffered to really get a grip on her, but during part 6 it all started to make sense. She isn't reliving some trauma when we see her covered in blood, she is fantasizing, drawn back to the memory of violence.
We've all been out with buddies and some other dudes gave you some looks and everyone knew, one wrong word and shit will go down. The only way it becomes unavoidable by default, is if any girl/woman opens her mouth, then there is literally no way a bunch of intoxicated guys will back down and the situation resolves peacefully. So Els, while standing next to the undefeated Light Heavyweight and Heavyweight contender, decides to take the lead and makes 100% sure the fight is gonna happen and then later even admits that it felt really good.
Then of course the bite while kissing, a bit too on the nose but maybe the developer wanted to check how many players will look past El's visuals to see the monster lurking below; she "just" wanted to taste his blood.
The whole pacifist shtick is not because she can't stand violence, her entire backstory contradicts that on multiple counts, it's because she's afraid that she loses control of herself when she is near violence. During the MC's fight, she doesn't give a single word of encouragement or motivation, instead the only time she opens her mouth is when she comments on the opponents injuries, that's where her attention is at.
Her deepest fear is losing control, so whenever that happens, like flying on an airplace, the new staff changing things at the center or a meeting with her dad, the face she puts on starts to crumble and she panics and starts to fantasize about her violent memories.
I never understood why Els first said to Alistair and then to Vi that she believes the MC is the only one that could "really understand her", but now that makes a lot more sense. She knows the MC has killed many people, was in several near-death situations, and has seen the darkest side of humanity. Els believes that she is so broken, that it takes someone with the MC's experiences, to not run away and be disgusted when she tells him the truth.
I have no doubt that there will be an Els ending, but I really wonder if there will be an Els happy ending or if the developer has some really fucked up shit in his mind.