Turning back to Agent Walker, it's clear that there is potential for a relationship between her and Jack. Granted, she does seem to display a bit too much emotional attachment to her fellow agents, and she latched onto Jack rather quickly under the circumstances, but she's about as good a match as there is. Her decision to interrogate Wilson outside of the legal boundaries is not a quick or spurious one; it's an effective way of showing that she has come to the same psychological conclusion as Jack. (It also seems to be preparing her for a role in the revived CTU, whenever that happens.)
Ultimately, even the poorly-executed Olivia subplot touches on the overall theme. Olivia stepped over the line when she chose to break the law to exact personal revenge in the name of justice. The President may have been conflicted, but in the end, she demonstrated the right kind of strength when she chose the law over her family. She found the line, within her heart and soul, that she wasn't willing to cross.
Of course, that focus on the theme makes the very end of the episode entirely appropriate. What better way to underscore the message that it comes down to one's personal choice? As predicted, Kim wasn't ready to let her father go, even if he was at peace with the idea. Which means, without a doubt, that Jack Bauer will survive to have at least one more very bad day.