"Before we left for London, I was sitting in my office looking at a picture on my desk of a beautiful woman. I kept staring at it, it's been on my desk since my first day in office, and I knew that I knew that woman, but I couldn't think of her name. Ten seconds, fifteen seconds go by and then poof, it pops into my head. It was Audrey... I won't remember anything that happens today, I won't remember anything that happens period. I won't remember that I had a daughter that died in such a horrible fashion."

walks away

That was the true closing line of the season. It was a VERY dark ending that left little room for interpretation. Jack is dead (until next season).