If I am given a video clip where a subject is looking at busy pedestrians through a window of a cafe and I am supposed to express nihilistic and/or existentialist thoughts running through the subject's mind. How can I express them without explicitly saying that 'Life is meaningless' or 'Whats the point of it all'?
If I were you, I'd try to imagine the sequence of (natural) thoughts that would get a person to an existentialist/nihilist frame of mind. It seems unlikely most people, upon viewing the bustle of a street from a cafe window, would just spontaneously arrive at the notion, say, god is dead.
Instead you'd likely start with a question about a specific individual -- "Where is the lady in the green coat going? Why is she in such a hurry? Does anyone *really know where they are going? Why does anyone hurry? Does it matter if we hurry or not?" etc etc et al, til you feel empowered or like crying.
I think the subject will in fact express his own ponders of reality. In order to avoid saying 'Life is meaningless' or 'Whats the point of it all' you need to understand that life in it self has no meaning. The meaning is given by the individual experiencing it. So my question would be "What's his/her meaning of existence?". The path we think we walk it's not actually a path in its self in which one walks from point A to B. The question to "What's the meaning if it all" wants to impose that we must do something to reach a realization of Why. "Life is meaningless" again imposes that it had a meaning in the beginning and now after some consideration that meaning had faded away. Meaning means that we must find a statement or action to life. The only perception of reality is what you have moment by moment. The rest are memories and assumptions. So to conclude the subject should say and think nothing.
What do the behaviours and symbols suggest, if you don't jump to conventional interpretations, reinforced by emotional responses? Who is even really awake in the scene outside, aware of their surroundings in the moment, instead of being absorbed in yesterday or tomorrow? What happens if we stop being automata, driven by the replication of our genes towards expressing post hoc rationalisation of ideas really just designed to express group allegiance, and instead react to this very moment completely engaged in it like we are creating a piece of modern art, or answering a koan? "But at my back in a cold blast I hear The rattle of the bones, and chuckle spread from ear to ear."