It should not be about Killing an attacker,it should be about disabling them from being able to continue to attack you.
Sparring is good.
If sparring is used for sport then it must have rules,and some vital targets are off limits.
If sparring is used for self defense then we must limit strikes to muscle mass areas and direct our strikes to vital targets.
Now to do that one needs a suit or to go through the motions with caution and care for your partner.
I believe in scenarios over free sparring as all points,attack and response ,or potential threat and preemptive action are controlled and can be replicated over and over.
When training I always strike vital points with care.
Strike the side of the neck,palm heel to the chin,fingers into the eyes as the head is driven back and down,knee to the groin as the hips jut out as head goes back.
If responding to a hay maker,strike to incoming arm,simultaneous strike to side of the neck ,go for a trachea grab,(or slide into the trach grab instead of strike to side of neck),sweep the attackers legs from the rear and drop down with control on the trachea and arm,you decide the ending.
I do not teach and I do not do attacks / strikes to body mass targets,except when Bumping ,using body and weight to make a shoulder strike into the attackers body center line ,drive them back,staying on them delivering elbows and knees to head ,groin,bladder.
We also use a lot of joint attacks,control,pain,breaks and take downs.
We do not like to teach and or engage in an exchange,or free sparring.
Kicks are low line ,to knee,or stop / check type kick,to close distance,make contact and destroy or create pain on target.
We only train to close the gap and work from the inside position.
My opinions based on what we / I do.