Supposedly that rapid sound was the echo off the metal roof. The first shots, this theory goes, would have been from the windows in the building under that roof.
No, I took a look at the impulse responses of the 1st few shots of the 2nd group, from one of the nearby (to Crooks) vids. (I’m into audio & acoustics and have such software / gear.) There are definitely at least 5 individual shots in that group plus the reflections of each. Another higher pitch sounding shot quickly follows with a bit different echo.
From other vantage points it’s possible the reflections (echoes) could be taken as additional shots. But from the nearby to Crooks vid, the shots even sound like exactly what one would expect from rapid trigger pulls.
https://www.youtube.com/watch?v=HbsFf96VnNc
(Start listening at ~ 0:50)
3 shots, 5 much quicker shots, 1 shot (higher pitch sound than any others), delay and another shot, sounds different yet again.
There is (or was) yet another vid where the 5 shot group sounds even louder relative to the other shots, but I can’t find it now & don’t have all morning. (Gotta take advantage of cooler temps while they last!!!) The link above is pretty definitive, in any case.