We amateur criminologist assume intent in every clue. But Luigi, just like Roskalnikov, probably was a mixture of guilt, incompetence, and mental breakdown, as the reality of his situation and its hopelessness took over his thoughts.
Anyone speculating too far should think how well they would sleep after shooting someone on the street and fleeing the biggest manhunt in recent history. Then ask themselves what kind of decisions they could make after 2 days of no sleep and immense stress.
Reportedly he is smart, so he probably knows the value of a good mystery.