This show frustrates me. If the entire season was as good as the finale, Continuum would be one of the best shows on TV. Instead, it feels like the writers dragged out the season and then piled on the answers all at once, because they couldn't think of a way to extend the crux of the plot over a dozen episodes.
Anyway, it would seem that Alec is going back in time to save Emily after all, although his attempt may not pan out. That scene did bother me, though: in the time that he was chatting with Kiera over using the device to save Emily instead of letting Kiera go home, the freelancer had plenty of time to shoot. Instead, he waits until after Alec activates the device to start shooting, even though a) it was obvious from their conversation that he was going to use the device, and b) it's futile to shoot after it's been activated. For a finale that was otherwise tightly written, that part seemed overly sloppy.
Although we don't know which moment Alec set the device to send him to, my guess would be that we'll end up on the roof or in the apartment before everything spun out of control. Then again, maybe he won't end up at the moment he intended to reach, just like his son got sent farther back than Kiera.
It would seem that Alec changing the timeline is the only way to get Kiera out of the freelancers' prison, but the next season could open any number of ways. It might follow Alec after he makes the jump, it might follow Carlos as he works with Julian, or it might skip over recent events and show us the "new" timeline that Alec created by going back to save Emily, and then start doing flashbacks to that period, just as the series has done flashbacks (forwards?) to Kiera's time.
Speaking of the scenes set in the future, did Kiera's husband look different in this episode? It almost seemed like he was played by a different, older actor, or something. I couldn't put my finger on it.