What were you doing during that Marikana massacure? Can you give a description of everything you did in that month. The weather, what you ate, the conversations you had etc?
You are comparing an average every day event with a traumatic incident. You are full of s**t.
In case you did not know, the average police officer do not go around on a daily basis shooting and killing people. So, he or she is likely not going to remember what they did on any specific day one, two, five, ten or twenty years ago.
But, ask them about any shooting event where they either shot and wounded or shot and killed a person, no matter how long ago. Same with any person who has been shot at, wounded or experienced a traumatic event.