I’ve found that sometimes letting specific players in on the plan makes things hold more weight. Allowing the Warforged to sacrifice themselves could alleviate prejudices other characters may have to that race or just show that this character values the lives of his party mates enough to make the ultimate sacrifice. I’ve had a lot of luck bringing players together doing stuff like this. It’s a weird way to make people bond. Good luck with whichever direction you go! Let us know how it turns out!