Responses

Did they preserve her, by any chance? Not nIcely or anything ofc, but put her in a box or something? That would give her some limited oxygen to go on.

i don't think they did, we can see her boby in the hole... But well, let's forget that xD
**SPOILER ALERT**
She may not have been dead when they put her in the hole, but she sure as hell would have been when he went to dig her back out. The human body/ brain cannot survive for more than 3-4 minutes without oxygen. So, even if she was a "free diver" (a person who can dive 10 meters and hold their breath for up to 2 1/2 minutes) which she wasn't, she could have only survived for a maximum of 6 1/2 minutes. They finished burying her, walked to the car, made out, dude drove away and drove back... yeah, she's dead.