Such screenshot occurs to justify its effect in the view of the audience from whom to expect mixed sentiments of tension, suspense, and desperation at the sight of a principal character whose constant presence seems to evolve in shadows or in a state of thick gloom while the other part of the atmosphere receives a faint amount of light to indicate how transitions take place.
Masumura Yasuzo evidently knew which perspective suits the scene that must evoke an image of stealth and treachery via a choice of lighting where the dark side makes a sharp contrast with the bright side. At an angle where the back of the man in focus forms the black before the others that make the white counterpart with their faces revealed, it feels that somewhere, something is bound to establish and sustain the conflict. Equivalently, the musical score in this portion of the story suggests undertones of pressure because of the human nature or instincts being portrayed by the conferring characters in a spot hidden from public notice. One necessarily observes herein that the manner in which dialogues blend with instrumentation rather sounds like there would be a consequence of opportunity or of mystery based on how words and music flow together to communicate the complex thoughts and sensitive gestures that could either make or break a plan in the end.
Moreover, all the men in this thematic image generally project an appearance void of pleasant expressions which I think further contributes to the heavy and serious air of encounter between them.