This is the first episode following the final break in the "24" production schedule. While all the episodes were planned out ahead of time, the producers apparently felt that the plans for the final six episodes weren't strong enough. One can only imagine that it has much to do with ensuring that the payoff for the end of the previous episode hits all the right notes. It also means that these final episodes will be a bit more scrutinized as a result.
After the stunning (and confusing) revelation regarding Tony at the end of the previous episode, the writers certainly have a lot to explain. They certainly make sure that his actions are covered, and they remind the audience that Tony's sudden intel on the attack on the White House was rather abrupt and poorly explained at the time. If Jack (and Agent Walker) had been in better shape, he might have recognized that Tony's explanations didn't quite add up. (Even so, Tony's regret over Jack's condition seems genuine.)
The subsequent argument between President Taylor and Olivia sounds much like the previous arguments between the president and Ethan, so much so that it seems to place Olivia in suspicion. She doesn't seem to want Jonas in a position to talk to the FBI, and if she is implicated, her attempt at stalling could have been designed to give the conspiracy time to eliminate Jonas from the picture. That turn of events was hardly surprising, but effective.
Jack's medical situation continues to be well-depicted, so much so that it seems rather hard to believe that Jack would be allowed out of anyone's sight and anywhere near the field. At the very least, it puts Jack in the proper psychological state to give Agent Walker a bit of experienced advice about losing a partner. She doesn't want to hear it, but it also serves to remind the audience of how much Jack has lost, and what he could potentially regain. His medical condition is the source of his self-realization, just as the current terrorist threats give the government reason to reconsider the importance of counter-terrorism.
It's always seemed like Agent Walker was in some kind of relationship with Agent Moss, and that it was part of the tension that was between them as a result of Walker's defense of Jack Bauer, and the same undertones seem to come into play here. It might also explain Walker's apparent interest in Jack. Could this be a part of her personality? If so, it's not a new idea, but it's an unfortunate one. Agent Walker has always had the potential to be a strong character in her own right, without some odd tendency for relationships with men in authority. (That's a little too close to the "Agent Scully" mode for comfort!)
It's a little surprising that Kim wouldn't take the initiative and opt to provide the bone marrow for Jack's treatment on her own, but at least her rationale is consistent with her relationship with her father. It's a bit disappointing, however, in light of Kim's family and the revelation that she has a daughter (named Terri, no less). In essence, she wasn't entirely honest with him, and didn't tell him something that could have changed his mind. It certainly doesn't help to redeem her character at this point.
It doesn't take long for Jack to put all the pieces together and figure out that Tony is working for the enemy. His confrontation with Tony is nice symmetry with the opening episodes for the season. Unfortunately, Jack's medical condition gets in the way, so the real confrontation is delayed for the future.