He must have been stoned to the point of being completely incoherent.
He can’t find his way back to the same apartment he was in earlier the same day & in which his child lives.
It’s a good thing for the ex girlfriend that he invaded the wrong apt. Sounds like he probably was homicidal.
Saw a pic of the apartments and they all look identical. I can imagine getting confused but not kicking down a door! Sounds like he was drunk/high and was ready for bear. The baby-mama is probably lucky it wasn’t her apartment.