I think a better idea would be to get rid of simple kills/deaths entirely, as the GM doesn't revolve around DMing (if you're playing it right). Instead give people points for being on the winning team, and being contributors to the gamemode.
For example, give Security points for being near the President and killing attackers while in his vicinity, and more points if the President survives. Give Terrorists points when the President dies, and more individual points to those who contribute to killing the President. Give Police points for killing attackers anywhere and the same points the Security get for doing what the Security do. The Vice gets points for not dying and/or killing attackers. The President gets points for his survival time, if he kills attackers, how far away the terrorists are, and more if he wins. Civilians get a small amount of points for killing anyone (less than any points the other classes get for kills), but the same amount of points as Terrorists for killing the President.
(I will not translate it into English) 
¿Por qué no? El español no es un lenguaje secreto
