I've said it before, and I'll say it again: Sam is the strongest "mission-oriented" guy in the whole Fellowship, heck on the whole good-guy side of the war!  Everyone else dithers about what to do, which way to go, trying to come up with other options.  Sam (and Frodo, too) realizes that there is only one task that matters, to destroy the Ring.  Without accomplishing that, nothing else matters.

   So here he has gone through a horrible time, and is terribly distressed, not to mention inexperienced and way over his head.  But in the end he remembers The Mission, and takes the Ring because that's the only option.

   Taking Sting and Galadrial's phial from Frodo is just another streak of hobbit practicality--he'll need them. Personally, I'd have taken Frodo's mithril shirt and rooted through his pockets for food and loose change, too, but we'll write that off to Sam's sentimentality and inexperience. (Hey, I'm a heartless orc, what can I say!)  All things considered, he's still doing just fine, here.

Matthew/Ugluk
http://www.larp.com/orcs/