Pardon me for asking, but if he was knocked out, how does he know the truck bomb went off later? Did he regain conciousness before the truck was blown up?
That's one hellva fine question.
He knows at one point there was a truck bomb because that is what he was told and then he later saw on the news. Basically he is saying there was something more that happened because he never heard a bomb but yet the building was shaking and debris was falling and it knocked him out.