Although it might sound disgusting, personal physiological issues are a major problem that everyone in Misrata has to face.
Snipers from both the government and the opposition are scattered throughout the city, and there are definitely not a few people who have been killed while going out to relieve themselves. Therefore, most people, including Gao Yang and his group, take care of their business inside the houses. It's a bit disgusting, but it's better than losing one's life.
After dealing with the disgusting tasks repeatedly, you get used to it and it doesn't seem so disgusting anymore, especially for Cui Bo. He had no psychological pressure doing something as vile, having peed his pants more than once during intense battles—not out of fear, but for lack of time to relieve himself. However, for some reason, this time Cui Bo changed his habits and insisted on taking the risk of going out to relieve himself.