Fair enough but none of that satisfactorily explains where the shooter was if he wasn't in an elevated position to the rear of the presidential limo.
He was on the grassy knoll.
Dozens of people ran toward the grassy knoll, including at least one member of the Dallas PD, toward what they perceived as the direction of one of the shots. There was a puff of smoke visible too. Many eyewitnesses saw it.
The grassy knoll was at the top of a somewhat steep grade. That slowed the crowd down.
There’s another theory that a shooter was inside a storm drain, ahead of the limo. There is such a storm drain there, but how true that component of the story is, I don’t know.
People who were present described four shots, two of which are almost simultaneous, but coming from different directions.