The stabbing happens off camera.  Also, during the time he spent inside stabbing her was cut out of the video and skips to him running off.  So we have no idea how long he was stabbing.  This is a pointless video if there ever was one.  Ex-boyfriend pays a young mother a surprise vist to show off his new blade.  He kept walking up and down the street waiting for the woman to come home.  As she and her little kid get out of the car and start walking towards the door.  He walks up to her while the child was in-between them.  When she saw the knife she did what any good mother would.  She forgot about her kid and ran off.  Leaving the kid with the knife wielding man.  He does slightly grab the kid and the kid started running.  Luckily, he had no intention of killing the kid.  But he got to the hoe after a short chase.  She tried to get inside the door to shut it even though the kid was still out there with the nut job.  After struggling at the door they both went in and he killed her while the child watched.  That should make for a nice supply of life long mental illness and make it unlikely for a normal life.