"We weren’t sure that we would have a fifth season when we were plotting out the end of Season 4. So we wanted to make the end of Season 4 as satisfying and as complete as possible, not knowing what the future would hold. Having said that, there are a couple of big, outstanding questions still in play. But I agree with you, if the show had not gone on past the end of Season 4 – although I’m very happy to say that it indeed will – but if it weren’t to go forward, I think I could be satisfied on some level, by that episode."
Vince Gilligan