Help with I think a space movie or a cave movie

I watched this movie at the movie theater around 2012 or 2011 but can’t be sure I’m almost positive it was a r rated movie. I can’t remember if it was a space movie or like deep in a cave movie all I really remember is it was a scary movie. I remember this one specific seen where a women and a man were fighting for a oxygen tank mask because they couldn’t breathe and they were taking really long turns basically fighting for it at the end they knew one had to die, only one mask at the end the man ended up wining the fight between him and the women and the women died suffocating to death i remember her flowing away which making me think it was a space movie but then I remember scenes of people walking or crawling I want to say. I also want to say their were like 6 more main characters like trapped for looking for way out which making me think it was like a deep cave movie.if anyone can help me or have any idea that would be wonderful!