Questions that Overture raised

[Kedjane]

In the cave with the 'metal monster' as Red calls it, Red talks about how 'hide and seek tured into seek and hide' and talks about 'the infected one from behind the metal door' and how he 'burried them benieth the ground'. So Red fought aginst the 'infected ones' and killed them. Mabey Red locked them in the metal door...

Yeah, I'm thinking Red escaped the Shelter and was hunted by some infected ones - killed or repelled them - then sealed them in. Perhaps the ladder leading out was broken when he tried to escape once?
I think it seems possible he made all the barricades keeping Philip out aswell.