why didnt he just kill the inspector before leaving? i dont get it
He went bonkers after his 2D childhood friend committed suicide, but yeah if he was sane should kill all the cops and inspector, then take a knife, put it inspector hand and stab himself just enough to live while lying under inspector corpse, waiting to get discovered.
This would prove that inspector force himself into his house, killed the surveiling cops and in struggle tried to kill Makoto because "Makoto ruined his career and tried to take vengeance".
win/win 3 total days gained.