Well, he way this question was asked, it's no the monty hall problem. The monty hall has a host who actively opens a door that is NOT the car (officer) here you have a host who forgets which door the officer is behind making it complete chance whether a soldier or officer is revealed. So you would have to reference this section of the Wikipedia summary of this problem:

*"The most commonly voiced objection to the solution is that the past can be ignored when assessing the probability—that it is irrelevant which doors the player initially picks and the host opens. However, in the problem as originally presented, the player's initial choice does influence the host's available choices subsequently.*

This difference can be demonstrated by contrasting the original problem with a variation that appeared in vos Savant's column in November 2006. In this version, Monty Hall forgets which door hides the car. He opens one of the doors at random and is relieved when a goat is revealed. Asked whether the contestant should switch, vos Savant correctly replied, "If the host is clueless, it makes no difference whether you stay or switch. If he knows, switch" (vos Savant, 2006)."

You see in this case, at least as I interpret the way it is written the 'host' is clueless, so it's fifty fifty.

If say the Enemy knows your sniper is there and PURPOSELY sends a soldier out first, THEN YOU SWITCH, because switching wins with a 66% probability.

So, depending on how you interpret this problem, everyone here was basically right.