No, you are wrong. A martial artist doesn't aim to kill, they
only aim to get ample time to run away if they start
attacking.
Firstly, when you whack, you don't kill. You only hurt them such
that it's so painful and they won't be able to chase you. You take
this chance to run away.
Secondly, you whack to throw them off balance. Balance in martial
arts is very important. Once you lose your balance, that's it. They
throw you to the ground, force you to a wall, you can't fight back.
You can't kick or punch, because everything will be well-defended.
The only thing you can do is to step on their legs in this case if
you are forced to wall. If you are thrown to the ground, you have
to make sure you get up fast enough and run away before they catch
you.
Thirdly, it's wrong to use self-defense just for whacking. It's as
good as showing off. The best defense in every situation is to
never provoke, or if the attacker decides to attack you, run away
instead. If he catches up, it's only then you attack to get him
off.
Lastly, there's more than just hitting, punching and kicking in
self-defense. You have to learn how to fall properly in case you
are off balanced by the attacker. You also have to learn to be
alert, street smart and use your common sense.
Alert 
meaning not SMSing or talking on the phone
when going to any place. Talking or SMSing makes you less aware of
your surrounding, and more prone to attacks.
Street smart some areas are known to be very
popular where fights can break out. Avoid these areas. It also
means that you have to know your way around a lot of places. If you
are not sure, just don't go there or ask a few friends to accompany
you.
Common sense don't take short cuts early in the
morning when it's still dark (if you have to go to work between 6am
to 7am when the sun has barely risen) or at night. Don't carry a
lot of cash with you and cover yourself adequately. If you are
going home late, ask your friends to accompany you, or take a taxi
home. If possible, ask someone to wait at the bus stop or the lift
for you.
