I don’t think you can trust their assessment of its speed. There’s no way to reliably determine the speed of an unknown object of unknown size and distance.
I was watching a meteor shower once, and after a few hours, the angle seemed to change. Instead of streaking across the sky, they appeared as a circle that got brighter and bigger before winking out....they were coming right at me.
This could explain the light in this video if it were a fairly large meteorite, maybe.
They enter at orbital velocity or higher, so yes. Mach 20 or 30 would be on the low end. Of course depending on their shape and mass they lose a lot of it on the way down...
The relevant regime for astronomical entities is in above the 'high-hypersonic' and into 're-entry speeds' (uber-sonic?). These are above Mach 25.
At these speeds, not only is the air no-longer considered an ideal gas, nor a two-temperature ideal gas, nor a dissociated gas (O2 and N2 become O and N along the wings), nor an ionized gas (electron temperature must now be considered), but rather a radiation dominated gas. Modeling these radiation dominant gases is very hard. As you increase the number of volumes to model, the computation load grows exponentially.
It's very unlikely but definitely possible. If the meteor is fast enough and targets outer earth atmosphere, it an enter outer atmosphere, slow down, light up due to friction, then escape earth atmosphere vertically. The only problem with this scenario is that meteor has to be much faster than Mach 2, unlike what pilots reported. But it's easily possible they saw a Mach 12 meteor and thought it's Mach 2.
