They are startled.

They react to the event itself, to the pain or the fear, and only much later, if at all, do they think about how it looks.

Guilt is the opposite.

Guilt is already thinking about how it looks before the dust has settled, because guilt knew the event was coming and has been preparing its account of it.

When Michael pushed me and, in the very same breath, before I had even found my feet, began loudly narrating a version in which I had stumbled, he was not reacting to an accident.

He was executing a plan.