WOW! Great frakkin' season finale! It will be a long wait till Sept...
Fewer people died than I expected. I was relieved to see that Andrea was not a goner, they need to hang onto her for a while yet.
The helicopter is a sign that there's some kind of organized attempt to handle the zombies, inducing them to migrate towards some gigantic firepit where they can be destroyed. Tough luck for anyone who's in the migration path, such as Our Heroes. I doubt it has anything to do with the prison we saw in the final scene.
On the subject of irrational characters, yes, it can be an annoyance if it it gives the writers carte blanche to just have the characters do any old thing for the convenience of the plot and chalk it up to zombie-induced PTSD. There haven't been any truly egregious cases yet, but a lot of marginal ones.
Rick not telling everyone what Jenner said: he gets a pass because like I said before, it's not clear how to interpret something like that. Jenner could be wrong or lying just to fuck with all of them, or even to induce them to stay and commit suicide with him.
Even if he's right, what does it mean? Does it mean that any of them can turn into zombies at any time? That would be my first assumption. Until it happens, there's no reason to depress everyone with that thought. I'm sure they're all thinking it now. And Rick did confirm that until he saw Shane turn, he wasn't sure what Jenner meant/if he believed him anyway.
The possibility that everyone on Earth became quickly infected with the airborne virus explains something I've been thinking is just a production convenience, the large number of uneaten or even partially eaten zombies. It's hard to tell how many of them have visible bites, given the state of decomposition.
Why aren't there more Bicycle Girls around? Because it would drive the budget through the roof of course, but now there's an in-story reason: a lot of people were turned by the virus immediately, without being bit and without dying first. That would explain why there weren't more pockets of survivors holed up in defensible positions, like you'd expect from a virus that had to be transmitted only by close contact.
The few survivors are doubly lucky: resistant enough to the virus not to turn immediately, and quick-witted/fast on their feet/gun-owning enough to avoid being killed by the zombies. If they are all fated to turn eventually, when the virus finally kicks in, that's not very lucky, more like slow torture, but it's possible some are naturally resistant to the virus entirely.
Another (more interesting) possibility is that doctors the hospital where Rick was staying managed to create a vaccine and experimented on patients to see if it worked. It killed the patients, but ironically, that's part of how
it worked. It killed Rick - that's why Shane didn't hear a heartbeat - and resurrected him, immune from the virus because the virus has already done its work. The vaccine doesn't prevent people from dying, it prevents them from becoming zombies after death.
This scenario also explains the still mysterious incident Shane observed in the hospital - soldiers gunning down non-zombified doctors. That was probably revenge after the doctors apparently murdered test subjects.
All this won't be revealed for a while - probably not next season, even - but it would be cool if how it's revealed is that Rick is killed. Everyone's waiting for him to revive as a zombie, Lori is freaking out and won't let Darryl put him down, then Rick wakes up - perfectly normal. And at that point, everyone remembers Shane's story about not hearing a heartbeat...
So, see yall back here in Sept!
I'm looking forward to the Season of the Prison. There's no reason you can't get 13 amazing kick-ass episodes out of a bunch of zombie apocalypse survivors hunkered down in a prison.