Ignoramus11290 fired this volley in
:

So,
in reality, what happens if I crash a running spindle into a vise or
something of that sort. Would the mill be ruined permanently?

Ig, it depends entirely on how fast your servo over-current detection or
following error aborts can handle the crash.

Hardly anything is "ruined permanently", so long as you're willing the
spend the time and money to fix it.

LLoyd