When entering a building with a king while he gets killed, it gives no extra population to the slayer. Game acknowledged that the king has died because all the landmarks go down and player gets eliminated, but no pop.
If anyone wants to check, go in game look for “Kouciii” or “tmb8” and find a game where teal was mali and blue french.
I have a clip unfortunately I cannot post it since I just created my account here.