devil: it's more about the game mechanics that leads the player to unarm Eileen and put her aside in some safe place to wait. Plus she is not protagonist of anything as the other female key characters of SH1 2 3. Is not a sexist game, but got some sexists aspects.
In SH1, Cybil help Harry and give the gun to Harry and Lise decided to help him, etc. they are partners. In SH2 even Laura got the power upon the story, she is not just a kid we must save. Should I talk about SH3? But in The Room, it's all about him, and Eileen it's just a passive character. In the beginning, she is a sexy girl next door - what for? At some point, it seams she will change something, as she can read the kid's writing, but at the end she just walk as a zombie. As long I like the story, there isn't the deep stories about the people involved, specially women, that creates "key points" and affects the end. What affects the end is how good fighter / wizard you are - the hero.
So in order to keep Eileen safe, you got to incarnate some Silverser Stallone!
I dunno.. Last time I played SH4, I played on Hard mode, equipped Eileen, never abandonded her and just rushed through the game. And guess what? I got a happy ending! Can't remember the ending's name but it's the one where Henry brings her flowers in the hospital.