Here be more spoilers...
My take on Don's move regarding Philip Morris is this: Firstly, he only found out about it by chance. When he did find out about it however, he soon figured out it was a play to get him fired. He reacted by, in a pretty desperate attempt, crashing the secret meeting. What he said during that meeting is also something I don't really see in his character; firstly, he said he'd publicly apologize and, secondly, he pretty much begged to keep his job.
I don't know. It just doesn't ring true to me at all. Here is this man who is nonchalant, demands respect and admiration, and is always in control. He is used to be, and wants to be, the big fish in the pond too. He also has a history of disappointing those close to him, and he runs away from trouble. All of a sudden this guy makes a complete turnaround; he begs for his job back, withstands humiliating treatment at work, and is generally seen as a pariah there. Don then fighting tooth and nail to keep that job?! He does this to regain his status at the agency instead of just seeking pastures new? I just don't see it.
