At its core "Yes." is about life. Not in a necessarily pessimistic or fatalistic way but rather on how individuals can come to grips and ultimately master a situation or an idea.
Pierre St. Jacques approached this facet primarily that things in life don't go away, they accumulate, one does not get rid of an idea, an obsession, or a situation, rather we create a new idea, a new obsession to take over our attention.
In the video it is when he realizes this fact that the main character stops feeling pain from the gunshots, he knows what he has to do, he can now play freely with the concept, he won't be getting rid of the other shooter, but he can control the situation and if need be switch to another idea. For the time being he revels in his new found power of being able to control the situation.
While working on the video a secondary theme emerged: In the video the concept of repetition is important in that it is often through repetition that belief or understanding is created, it also - unfortunately - underscores the easy amnesia that we have in not seeing things for what they are initially but rather is seeing them through what we already know. This can be seen in people's quick attention span to media violence or various tragedies where a few weeks after all is back to 'normal' the incident is forgotten, it doesn't hurt anymore.