[He sees the anger and it surprises him for a moment but then so does the answer.]

...why would they assassinate me? Wow..does messing with you when you are drunk make even your ancestors mad? No wonder the junior Lans were so shocked when they saw me tied up. They probably thought I was being attacked and you were protecting me. And here I thought you were just being..odd.

[If that is the case then he is never letting lan Wangji ever drink again. He doesn't want to be killed by some mad ancestor.]