For humans this probably would be mortifying. The beast version of Vincent is a bit human. But his instincts... yes. He might not like it, but he will submit. He lost and this chimera thing is stronger than he.

....And ultimately, this had not been a battle between enemies or about territory or food.

Slowly, he relaxes. The tip of the tail swishing, a few more rumbles and then... silence.

Vincent... doesn't need to be knocked unsconsious to regain control. Sometimes it's random how long this lasts. At other times it's a matter of energy to sustain the transformation... perhaps. In many ways, it's how his mind slowly awakens beyond its fragmented and piecemeal awareness of events during his transformation. The more it does, the urge is strong to assert his humanity.

That in itself starts an irreversible return to his human form. Even if he were aware fully of his plight, it wouldn't change anything. Sephiroth will find the energy that first surrounded Vincent is now dispersing, melting away the purple behemoth-like beast and returning to the shape and clothing and flesh of humanity.

...There's hardly any difference in the taste of smell in many ways.