Vmc is an aerodynamic control speed.
No, Vmc is a certification value. The actual aerodynamic control speed varies with a number of factors, ranging from CG to density altitude, flap position, gear position, and gross weight.
A large part of this discussion (which really ought to be centered on the 340, rather than aerodynamics or procedures) has been about the ability or efficacy of preventing a Vmc roll following engine failure while taking off at speeds less than the minimum single engine control speed.
The airplane will not, as a rule, snap roll inverted and crash. Control may be lost faster than you think, however. Regardless, why would you want to find out? It seems the point of the questioning is to see if you can take off at a ridiculously slow speed and still manage to pull back both engines in time to prevent a roll. Rather than do that, how about using a longer runway and flying the airplane at a speed which does maintain control...and flying the airplane instead?