They did say the prison would be in Season 4, now I get it.
In the comics, the Gov tears the walls down with a tank... not sure he'll have the help he needs to do that, but in the comic Andrea is alive and well still...
And the whole Rick-Michonne thing was explored a little bit, I think, in the comic.
Anyway, one good thing we can take away from the show is that the creator is not afraid to totally throw us all for a curve that are familiar with the comics. It wouldn't be any fun if we could predict exactly what was going to happen.
Still shocked at Andrea... and still shocked with the thousands of bullets flying during the prison raid that not one person (except the the Woodbury kid) bit it (after it was over)... the prison trap wasn't even very effective.
Of all the episodes this season, I'd rank it near the bottom. At least it builds a few story lines for Season 4!