The OP is communicating three things very succinctly here that may be viewed as a reflection upon himself. A desire to numb the pain, ie pharmacy; a desire to quickly document his world and his pain, ie 1 hour photo; his desire to escape, ie the car; the sense of isolation he feels, ie no people; and the wall between him and the rest of humanity, ie the side of the building.
The near uniform greyness of the exposure represents his inability to truly feel and differentiate between all these feelings, as they blend into one homogenized tonality of soul. An unfeeling grey. He sees a difference between these feelings, but he does not feel a difference between these feelings. This took little time, but in fact, perhaps, it took his whole life. It was thought out, because he must think his feelings instead of feeling them. He hopes to dip into humanity, the human genome and regain a feeling for who he is. Walgreens looks on, off the screen away from him. He chases after visually.