existence precedes essence

As of now, I believe the turning point for Mersault was when he he said "I had knocked on the door of unhappiness". At this point I felt he realized that his actions have consequences and/or benefits. The old Mersault would have just gone with whatever happened next, never recognizing the consequences his actions had, however the new mersault sees that he has free will and the ability to shape his future. By seeing this, I believe Mersault will want to take matters more to heart, and provide essence to his existence by doing so.