Any time a bullet pushes incompressable (mostly liquid) tissue out of the way, there is a shock wave that travels away from the wound track and damages other stuff, over-stimulates nerves, etc.
This can happen at speeds far below Mach 2.
If you know of some scientific definition of "hydrostatic shock" that requires 2,200 f.p.s. at impact, please post a link.
She makes a compelling case...