Комментарий к Берешит 19:21

גם לדבר הזה CONCERNING THIS THING ALSO — Not only will you be saved, but I will also save the whole city for Your sake.

ויאמר אליו הנה נשאתי פניך, from this verse we may deduce that when G’d dispatches an angel on a major mission, He gives the angel some discretion in the manner in which he is to carry out the task assigned to him. The angel or angels may use their own intelligence in this respect. Clearly, an angel is not like a golem, but is an intelligent being.

Also … regarding this. Hashem agreed not to overturn Zoar at all.