https://www.cbc.ca/news/canada/manit...cing-1.5165442
tl;dr
Intruder "enters" a residence, stabs the occupant in the head while they're sleeping. Occupant wakes up, fights intruder, and ends up getting a hold of the knife and stabbing the intruder to death. Sentenced to 5 years for manslaughter.
Cases like this are always tough. If someone's trying to kill you (safe assumption when they break into your house and stab you in the head), odds are your adrenaline is pumping and you're not about to stop fighting to assess the current level of danger every half second to be sure you don't overstep your legal rights. You're scared to death and someone is there to kill you. You react.
Maybe this is where I'm far too right wing, but I think breaking into a house and assaulting the occupant is an immediate forfeiture of your right to live.