[Pi]

So first retaliations are forbidden. The Geneva Conventions forbit retaliation attacks againt civilians. And a retaliation against military force is no retaliation but normal combat action.
As HP said already, even standard procedures have to be ok. You just can't fire on any target if you can injure or kill civilians, except, if your target is a legal military target. And it seems to me that an own, broke down tank isn't really a military target...