At this point, it feels like the producers and writers made a conscious decision to polarize the audience, as if recognizing that most of the season had lulled the remaining fans into something of a hazy stupor. If nothing else, Jack's decision to embark on a suicidal killing spree has definitely gotten the attention of the viewership.
While one would hardly want to justify the current direction taken with the character, there may be some method to the madness. (And in keeping with the track record of the writing staff, it could very well be unintentional.) If one of the questions since the first season has always been where to draw the line between the demands of service to one's country and unjustifiable violence, then the writers have concocted a scenario where the audience is actively asking and answering that question.
For example, ever since the murder of Renee Walker, fans have debated Jack's single-minded vendetta and whether or not it fits the character's ethical history. While a large majority of the fans appear to object to the notion of Jack Bauer pursuing personal vengeance over justice, there have been many passionate defenders.
It's going to be interesting to see if this episode changes anyone's mind. Certainly there is plenty of evidence to support the notion that Jack has gone completely off the rails, far beyond anything he has done in the past. While it's true that Jack has been spectacularly creative with his interrogation and self-defense techniques, his methods have seldom exceeded the needs of the moment.
And it should be admitted that Jack has, on several occasions, allowed personal feelings to influence his actions. Yet it should be equally noted that his actions, even then, were bounded by his sense of duty. For example, while one could argue that Jack ultimately killed Nina Myers under questionable circumstances, it was something that came up in the course of a larger crisis. Jack was not single-mindedly chasing down Nina in the days after Teri's death.
In the last few episodes, one could have made the argument that Jack was serving two purposes by murdering Dana and Pavel: exacting revenge while also retrieving the evidence necessary to ensure the right people were brought to justice. In fact, that argument has been made, even if many were unconvinced. But that stopped being true as soon as Jack handed the evidence over to Meredith Reed, yet still insisted on continuing with his search for vengeance.
Nothing that Jack does in this episode is devoted to the cause of justice, unless one is speaking in the Old Testament sense. It would appear that everyone involved in the production is aware of this fact, because they ensure that Jack looks as terrifying as possible during the abduction of Charles Logan. Sure, he let the Secret Service personnel live, but as Cole says, that's not really enough to vindicate Jack's actions.
Of course, that also comes before Jack's brutal slaughter of the Russian delegate and his bodyguards. It seems like the only people who survive are the ones necessary to keep the plot balls rolling. But that's just the usual brand of convenient writing on "24", so it's hardly unexpected. Jack's decision to eviscerate Pavel and then kill the delegate by impaling him with a fire poker is way beyond his usual clinical techniques.
And if anything, this continues to prove the point that so many fans have been making. Why would this particular incident break Jack so badly that he would lose his humanity and care nothing for his own survival? He's been betrayed by presidents before, he's lost loved ones before, and while he's been willing to die for his cause, he's never actively sought death. Along with the level of violence, it's all part of the conclusion that the writers are forcing what seems to be a disproportionate response.
Events have spiraled so far out of control that it's hard to imagine how the writers could have Jack come out of this with any hope for the future. Then again, it's already been said that the "24" film franchise would stand on its own, completely aside from the continuity of the series. If that's the case, it's entirely possible that they would have Jack die, ending his story with one final tragic meltdown.
It wouldn't be the ending the fans have been waiting for, but it might just be the only ending the writers have left themselves.