Snipers shoot from a long distance, but due to their powerful telescopes, they are able to watch their targets carry out their daily routines and they are able to see their bullets hit the targets and the effects the hits have on the targets. They see the results of their actions without have to make personal contact. Since they do not make direct contact with the enemy but have to deal with the results of their actions at a personal level, they may be classified as having semi-personal contact with the enemy.
The soldiers who deal directly with the enemy are the Special Forces soldiers who work stealthy behind the lines. Most of their killing is done hand-to-hand so they may be classified as having personal contact with the enemy.
Practically anyone may be trained to be a soldier, but it takes a special type of person to be a Special Forces soldier or a sniper. It is much easier to deal with killing a person if you have no contact with the person and do not have to see the person die, therefore, field soldiers usually do not have problems in dealing with the psychological aspects of killing the enemy. Even with their increased personal contact, Special Forces soldiers and snipers also do not have psychological problems in dealing with killing the enemy. This is because they have been specially screened to find the persons who can deal with the personal killing and they are specifically trained to deal with the psychological aspects. As related to the martial arts, it also takes a special type of person to deal with martial arts that use increased levels of personal contact.