And he is among maybe two people who is not grabbing his head/covering his ears from the loud explosion. This has bothered me from the minute I first saw the picture of him stepping over the wounded guy in the grey hoodie. There was also a bald guy standing at the rail who doesn't react for four or five frames...lower right corner of the picture next to a woman who is still facing the runners and has her cellphone up and facing the road.
At the second seen there are two different men that also seem to be not reacting. There is balding tall man in the dress coat, behind DT and up against the brick wall...he is facing past the immediate carnage and down toward the first blast site.
Then in the really good picture if you zoom out and pan right there is a heavy-set white-haired man, standing in the intersection, who is facing the corner where DT and the man behind him. That man almost seems to be smiling.... That is as much as I will say on this for the time being.
Pictures are moments in time, not the whole story. They are split seconds captured by a camera. I am really tired of innocent people, victims psychologically, if not physically, being picked over like they are suspects. Has nothing been learned from the high school student and his coach who were falsely accused, their faces put on the cover of the NY Post? Or from sweet ST, the missing Brown student, who was falsely accused (and whose body was pulled from Narragansett Bay two days ago)? His family was put through hell.
What you perceive as a smile was, in all likelihood, a grimace as he witnessed the horror scene all around him. Regarding the man you describe as "facing past the immediate carnage and down toward the first blast site," is a person not allowed to look back to see what is happening? Maybe he was with other people and they became separated in the chaos and he's trying to locate them. As for the person with his/her clothes torn off, who is running away from an explosion, it's called the flight half of the fight or flight response. People react differently in traumatic situations; it doesn't make them conspirators.