So, it's quite modern, probably 2020s or late 20-teens. There's some kind of apocalypse happening, and they're all preparing to go and live in an underground bunker in perpetuity. I think not all of them can go in. It's quite funny in a wry sort of way, and right near the end there's a really funny scene where the door into the cliffside opening to the bunker is finally closed, and it's like a scene from Thunderbirds... you're expecting it to be really monumental, but it just drops down like a cardboard piece of set.
The main character (male) has been having a relationship with a woman and there's some sort of drama about her going in and him not, or vice versa. Some of them don't believe it's right to go in. They all watch 'the last sunrise together'.
Any ideas?