Are you familiar with the flow phenomenon of
choked flow, where a chamber pressurized with compressible gas vented to a lower pressure has a maximum velocity at the choke point of the vent? And that this behavior has been demonstrated time and time again since
the 1880's.
Except the video I linked, they admitted they’d lost the vacuum after ignition, so it was just another staged dumbshow.
Again, in the “endless absolute vacuum of ‘space’” there is no ignition, only instanteous skin ripping off your face and dispersion of molecules.