Yes... I know. But, as I see it... [She pauses, unsure for a moment as she doesn't really know their situation at all, but... she can relate, in any case, and only tell him what she believes.]
I think, if he was here and you weren't... he'd still wish for you to be here. That even though leaving here means going back to a place where you won't be-- even more, he's happy for your time here. That it's something precious, for both of you. It's natural to feel that way. Even if it's on borrowed time. [The last comment is directed as much at Arthur as it is to herself - after all, she feels the same way...]