I believe those were Nicholas’ guts we saw the walkers tearing into and Glenn, under him, was reacting in horror not pain. But as much as I want Glenn to survive, I don’t see any plausible way for him to get him out.
Exactly. There were just too many of them. It's not like they got full. Glenn had nowhere to go.
I'm going to have faith in the writers though. They've pulled some good stuff out of their hats and they seem to know the expectations of their fans.
Smell has a lot to do with walkers attacking.
Smearing gore on themselves was how they walked out of the building in Atlanta in season one. Michonne used her walker “pets” to cover her scent and she also approached the prison the first time covered in gore.