Have to agree with Rosie 125
It was done by a left-handed person from behind (never saw it coming) so therefore it would be ROGER.
That's what I was saying think about not being seen. A Left handed person has to strike coming from the right of a person for maximum force, otherwise they would be doing a backhanded blow. If a lefty did that, they would have to pass them right in view of the mirror in order to get on their right hand side. so would be seen.
A right handed person could strike from the left hand side for maximum force, not have to pass them in front of the mirror, and not be seen.
I think that's what I mean . . . . possibly