Why did the shopkeeper of Longmen Escort Agency kill Lu Sanjin?

Revenge for yourself. Duke Du and Lu Sanjin are characters in the TV series Longmen Escort Agency. Duke Du is Lu Sanjin's uncle. Dugong killed Lu Sanjin, because one of Dugong's and Lu Sanjin's fathers had to enter the palace, and it needed to be decided by lot. Uncle Lu Sanjin tampered with the lottery ticket, and Lu Sanjin's father took out the long one, but because of his tampering, Lu Sanjin's grandfather thought he was smart, so he sent him to the palace. Dugong thinks it's unfair. In order to get revenge, he decided to kill Lu Sanjin and was finally killed by Lv Qingcheng.