Once again you make the foolish mistake of assuming what a witness has said is an established fact. You'll never figure out the JFKA as long as you have that mindset.
No assumption at all. I take the evidence at face value and examine the rest of the evidence ce to see if there is other evidence that conflicts with it. I reject it only if there is a good reason ie. other evidence that conflicts with it. I don't assume that it is wrong because it is a human witness like you do.
There's no reason to think the position of the car would have been "seared into their memories for life".
Unless you were there, how would you know? Those who were there - like Mary Woodward, John Templin,Ernest Brandt, Tina Towner, Linda Willis, Rosemary Willis, Bob Jackson and others who made Living History contributions to the Sixth Floor Museum - would say otherwise.