Maybe I’m confused but when the TB closes it technically reverses the flow (hence it going back at the turbo). There for, it would not flow against itself in order to get back.
Even without a BOV, when the TB closes the flow will be reversed back to the turbo unless the pressure is so goddamn strong that it forces the TB open.
Another thing I’d be interested in knowing is how much of the pressure actually gets dumped because I have a feeling not all of it gets out (think of how big the IC is and how much piping there is) for all of that to discharge every so briefly when the BOV opens seems unlikely to me considering most BOV’s have what a 1’’ opening ?