The main thing I see that counts against using this recording to determine what happened is that Pruszynski wasn’t even in the same room when the shooting happened. He was in a crowd, walking down some stairs that led to the hallway that led to the pantry where everything took place, and he wasn’t even actively trying to catch the sounds properly. I haven’t actually heard it myself, but apparently the recording was of very bad quality.
What I wonder about is the comment that “Sirhan fired eight shots in total, yet 14 were found lodged around the room and in the victims.” If there really were fourteen bullets found, then that would certainly mean that somebody else was firing a gun there. But I haven’t seen anything anywhere else saying that any more than eight bullets were found.