Is this him committing suicide, but with dignity? Or truly believing that he's no longer the one that can be the hero to the fleet.

Well, Bill is the Admiral and if the ship is going down, so to speak, he's going down with it. Not to mention, he's not going to allow his people to fight and die while he's in the relatively safety of the Cylon basestar.

Speaking of the basestar, between the promo and something I just found out, I think there is the potential for some very interesting scenes on that ship next week.