So you also accept what she said about the motorcade stopping dead still, Andrew?
Her statement about smelling gunpowder is independent of her observation that the motorcade stopped. At least three others reported smelling gunpowder after the shooting. Sen. Yarborough, Tom Dillard, and Virgie Rachley.
Dillard was familiar with rifles and said this (6H165):
Mr. DILLARD. ...
I might add that I very definitely smelled gun powder when the car moved up at the corner.
Mr. BALL. You did?
Mr. DILLARD. I very definitely smelled it.
Mr. BALL. By that you mean when you moved up to the corner of Elm and Houston ?
Mr. DILLARD. Yes: now, there developed a very brisk north wind.
Mr. BALL. That was in front of the Texas School-Book Depository?
Mr. DILLARD. Yes, it?s rather close-the corner is rather close. I mentioned it, I believe, that it was rather surprising to me.
Virgie Rachley's FBI statement given Nov. 24/63 (CD5, p. 67) states:
"She recalled that after the second shot she smelled gunsmoke but did not know where it was coming from."
Yarborough was interviewed by the Houston Post and attributed this quote to him in a Nov 22/63 story:
"A few instants after the shots, Yarborough said, the President's car spurted ahead at a very high rate of speed, with a Secret Service agent lying on the back of it, and beating his fist on the back of the car, as if in great despair and anger. Yarborough said he could smell gunpowder in the area of the shooting. 'I could smell powder all the way into the hospital,' he said."
Whether it was actually detectable as a smell all the way to Parkland is a little more difficult to accept. It may have been a brain memory that was seared into Yarborough's consciousness at that moment.
There is no reason to believe that gunpowder gases propelled at great speed from the muzzle sticking outside the window would have filled the inside of the 6th Floor of the TSBD. It would have spread out and down onto Dealey Plaza. So it does not surprise me at all that gunpowder smell was detectable around the TSBD.