Resuscitation
Tired of accidentally killing soldiers when you want to get a high ranking? One of the basic weapons you start with can prevent that. First, shoot a soldier until the near-death skull apears. Then, switch to the Stun Rod. Go up to the dying soldier and electrocute him until half your battery is dead. This will revert his status from near dead to stunned, allowing you to move on without worrying that the enemy will die.