These angels had power; they say directly they were the ones who would destroy the city. That power and the authority to do that had been delegated to them by God. They had authority to get Lot and his family out of the city, and they had delegated authority to punish the cities.
Consider that God did not script everything out for them. What does that mean to us? Like men, these angels had minds, and they had to think things through. Is this in line with the charges that God gives us? In the situations we find ourselves in, we have to think, "Would this be okay? What are our alternatives here?" In other words, the angels did not just march into the city, commandeer what they needed, grab Lot by the seat of his pants, and throw him unceremoniously outside of the city. They had the authority to allow Lot choices, and they worked within the framework God had given them. This means that angels have minds with which to assemble facts, to think, and to devise alternatives.
John W. Ritenbaugh
Image and Likeness of God (Part 3)