I was once a big time smoker, and it's true. Unstoppable craving. When that chemical "urge" strikes, STAND BACK..... smokers will cut short phone calls, abruptly end meetings, vacate a lunch table, abandon hallway discussions, jump out of cars, freeze on the front steps, etc., etc. So I agree, Obama's performance had the distinct look of a nicotine "fit". Sadly, I used to do all those things. If this was the reason for this atrocious behaviour, I feel sorry for him. It's a vicious addiction, and pure poison to the body.
On the other hand, he may simply be the product of a lack of etiquette and the social graces in his formative years.
As a former heavy smoker I know that he could get through these things if that is indeed his problem. Just needs some nicotine gum stashed in his pocket. It staves off those intense cravings and is socially acceptable, albeit very addictive itself....@#$%
As a former smoker, you have far more insight into it than I have. All I know is that the smoker I was close would periodically have a craving that Could Not Wait. But as you say, with Obama it might or might not have been that. He may just have been totally irked with BC for doing effortlessly what Obama needs a teleprompter to do just so-so...or worse. Put two full blown narcissists together at the White House podium, and anything can happen.