Two things:
- Why did Roger topple his drumkit at the end of the show?
- They walked off very fast after Jailhouse Rock - Freddie and John were offstage before the playback of GSTQ even started. It's difficult to say why, so this one doesn't really demand an answer, just speculation. Maybe this just what they did at the time, and they'd yet to start standing at front stage and bowing like they were by 1977 (we have no other footage of God Save the Queen from 1974 through 1976 - Hammersmith and Hyde Park both lack it). Or were they particularly eager to get going that night because of a fairly unresponsive audience?
Not long after the show Brian said the band didn't enjoy the shows because the film crew was in the way.
But I don't think it was as bad as how Neil Young described Woodstock, with the cameramen literally being in your face with the apparent inability to locate the zoom function.
GSTQ was a new addition to the set on the SHA tour
maybe they still had to learn the stagecraft which was evident on later tours
or maybe taking bows wad just not the done thing at the time
it wss 40 years ago..