I had a really difficult time following this one, at first. The segue from the book on the frig to the actual story in the book confused me, mainly, i think, because of the mention of the photo of Rina and her roommate so close in proximity to the story of the book: the two similar enough to make me think it was a flashback rather than the content of the book (actually, i went back and forth several times: first thinking it was the book, then i thinking it was a flashback). I don't think i'm the only one who had this problem, as several people got in mind that you stay alive as long as your soul is intact, when, actually, there was nothing in the story to indicate this. I think that notion (for me, at least) came from my confusion where i thought Rina was long-lived because the part mistaken as a flashback was obviously decades earlier, so for a while there it made me think they lived for as long as their soul was intact.
ANYway.
So while the ice cube was no surprise to me, the cigarette box was. For me, that was the most beautiful part of the story. I ended up liking this story, but i thought it could have been much shorter and retained its depth. It thought it was very creative, even if it did put me in mind of Pulman's soul concept. I really loved the author's interpretation of how the historical characters's souls were embodied.
And, as usual, great insight, SC! I really enjoy reading your critiques!
Oh, and as to the question of her soul becoming steam—the story states that you have to keep your soul close in order to survive. As steam, her soul would have been difficult to contain and keep constantly near. =)