they were taking elements from the comic, not following it.
Tyreese was the one that got the Katana. Hershel was shot and Beth died.
There was a tank, but no shells. However, this episode was about as close to the comic storyline than any of them.
I saw one of the executive producers on TALKING DEAD a few months back and she said they’d have a lot more leeway in the fourth season because the comic book line ended. Obviously I don’t read the comic.