It was TTM's blow with 2x power redirected back at himself. Even TTM himself stated that while discussing Garou with Saitama in that hospital. If Garou didn't do that in their fight, TTM would have hadn't mentioned the 2x strength stuff. The scan illustration can be explained that it was just inconsistent drawing. Also,
in this scan, you can see that Sonic was apparently punched by that muscular guy and we even see small traces of blood from him. However; it turned out that it wasn't the case and he just
blitzed them before they could react.
Also, what about my other points regarding the vital points?