(SPOILER) A Bioshock 1 question?

I understand this great game, but one thing I don't get is when you kill Andrew Ryan, what stops him from being revived? I know he switched off the vita chamber in his office but why can't he just respond in another one, cause some places where I died as Jack there was no vita chamber that close by but it still just takes you to the one that is closest, so why not the same for Ryan?