[Gen 18:21 YLT] (21) I go down now, and see whether according to its cry which is coming unto Me they have done completely -- and if not -- I know;'
We know that the men of Sodom did in fact attempt violence against the angels of the LORD:
[Gen 19:1-13 NLT] (1) That evening the two angels came to the entrance of the city of Sodom. Lot was sitting there, and when he saw them, he stood up to meet them. Then he welcomed them and bowed with his face to the ground. (2) "My lords," he said, "come to my home to wash your feet, and be my guests for the night. You may then get up early in the morning and be on your way again." "Oh no," they replied. "We'll just spend the night out here in the city square." (3) But Lot insisted, so at last they went home with him. Lot prepared a feast for them, complete with fresh bread made without yeast, and they ate. (4) But before they retired for the night, all the men of Sodom, young and old, came from all over the city and surrounded the house. (5) They shouted to Lot, "Where are the men who came to spend the night with you? Bring them out to us so we can have sex with them!" (6) So Lot stepped outside to talk to them, shutting the door behind him. (7) "Please, my brothers," he begged, "don't do such a wicked thing. (8) Look, I have two virgin daughters. Let me bring them out to you, and you can do with them as you wish. But please, leave these men alone, for they are my guests and are under my protection." (9) "Stand back!" they shouted. "This fellow came to town as an outsider, and now he's acting like our judge! We'll treat you far worse than those other men!" And they lunged toward Lot to break down the door. (10) But the two angels reached out, pulled Lot into the house, and bolted the door. (11) Then they blinded all the men, young and old, who were at the door of the house, so they gave up trying to get inside. (12) Meanwhile, the angels questioned Lot. "Do you have any other relatives here in the city?" they asked. "Get them out of this place--your sons-in-law, sons, daughters, or anyone else. (13) For we are about to destroy this city completely. The outcry against this place is so great it has reached the LORD, and he has sent us to destroy it."
Is it possible linguistically and contextually that in Genesis 18:21 the angel of the LORD is saying that he intends to see if the men of Sodom will attack him?