In the german interview that just happened some minutes ago he mentioned that he had no clue if/when he broke the sound barrier, he was way to busy trying to get the tumbling under control. He also was shortly before passing out and still somehow managed to trick the G-Meter so it doesn't go into emergency mode, that would happen with 6s of continuous tumbling, he managed to stop it for a few seconds every now and then, thats why it didn't throw the stabilizing chutes.