Death Match win condition

[Bad Hair Day]

So I was playing a death match against 3 computer players. One of them I attacked and mostly wiped out, but rather than mop him up, I moved on to another player. The 2nd player I mostly wiped out, and during the battle that player "quit". There is a line thru their name in the box on the bottom right and their units no longer take any actions.
What triggered that player to quit? I don't think I did anything different against that one than the first one. Was it killing all their castles?
When I look in "Game settings" it says "Conquest game" with "win by destroying all units, buildings, villagers and boats." Which I am nowhere close to for the one who quit.

What's up with that?

 

[Bad Hair Day]

So I noticed it was that I had to kill certain buildings to win the match. Is it the Town Center? Where workers are made?

 

[HongeyKong]

Death match or sudden death?

 

[Bad Hair Day]

Death match. Where you have TONS of resources to start with.

 

[Lokalo]

Well AI have some things probably in consideration when surrendering, score difference, maybe pop difference, vill count, even if it is conquest it makes no sense to destroy every building and unit, is waste of time, mainly what conquest does, it doesn't let you win by wonder or relics, I don't think it affects when/how AI resigns