At the deepest part of me...or at least at the part of me that does this...I am convinced you cannot act in a vacuum. More accurately, I am convinced nobody wants to act in a vacuum. And it is no sort of treason to say that true excellence in this endeavor of theatre cannot be achieved in a vacuum.
And if professional actors say otherwise, I feel emboldened enough to say I think they are full of sh*t.
Acting is not meant for a vacuum. I stand by that.