What did SS agent Kellerman mean by, "A flurry of shells come into the car?"

[Bill Chapman]

          Emphasis being on Connally's "THEY're....."

It's natural to expect more than one shooter if more than one shot has been heard, especially at a car carrying the POTUS.

[Jerry Freeman]

It's natural to expect more than one shooter if more than one shot has been heard, especially at a car carrying the POTUS.

Absolutely! Then came a 'flurry'.

[Jerry Freeman]

Representative FORD. You don't recall precisely a second shot and a third shot such as you did in the case of the first?
Mr. KELLERMAN. Let me give you an illustration, sir, before I can give you an answer. You have heard the sound barrier, of a plane breaking the sound barrier, bang, bang? That is it.
Representative FORD. This is for the second and the third, or the flurry as you described it?
Mr. KELLERMAN. That is right; that is right, sir.

http://mcadams.posc.mu.edu/russ/testimony/kellerma.htm
At the close of Kellerman's testimony..a 'Mr Smith', a 'Mr Murray', and a 'Mr Craig' are present and mentioned....

The CHAIRMAN. Mr. Murray, can you think of anything?
Mr. MURRAY. No, thank you, Mr. Chief Justice.
Mr. SMITH. Off the record.
(Discussion off the record.)
 Mr. CRAIG. Mr. Kellerman, is there any special agent in charge of the protection of the person next in line in succession, to your knowledge? 

I looked up the Commissions staff members and couldn't find them listed as assistants.
Who were these guys?
 

[Royell Storing]

I reversed the windshield crack pic - then over-layed the pic onto the limo before it left Dealey Plaza - and then captured an image with the pic partially transparent to compare the crack lines...
Looks like a match, and a result of the flurry of bullets!
No wonder they tried to ship out the Limo quickly and repair the incriminating damage...

     The Illuminated Center of your Red Circle in the Altgens Pic is too low to match the Windshield Crack/Hole Position in the other Photo. The Illuminated Center of the Red Circle is roughly at the same level as the buttocks of SA Hill and slightly lower than his elbow as he is leaning over the spare tire. Plus, it is Far Below that metal strip that stretched across the Limo and helped support the Limo Top.  In the Altgens photo, this puts the height of the Illuminated Center of your Red Circle at a little higher than the trunk lid of the JFK Limo. This is not close to the Height of the Limo rear view mirror Crack/Hole we see in the other photo. Either the center of that Illuminated Red Circle is displaying something else, or we are looking at 2 different Cracks/Holes in the windshield.