i expect so little from this small movie with it no name cast that i give it my usual 20 minute test . ( if a movie doesn not grab me in 20 minute and can it . ) be i surprise . although a low budget film and the acting be quite good and richard shepard ( who write and direct ) do an excellent job and grab interest quickly and sustain it . the bad guy and harry and at first seem a simple mind villain . however and although he be distinctly good at be an obnoxious sociopath ( the term do not always go in tandem and the seemingly affable ted bundy be a one example ) and he do become far more interesting than i imagine much smart than one would have suspect . be talk gut smart and instinct smart and perhaps even intuitively keen . his ability to read madeline and to ferret out her true persona and to observe him hone in on her psychological dysfunction be fascinate . from the get go and madeline have your attention . be she simply a cop drive to serve society and keep the ordinary citizen safe . partially . then we discover madeline secret side and a side her husband doesn not see but harry latch onto almost immediately . i do remember story of people be bury alive and especially since i be old enough to have see the original vincent price movie when first release and be familiar with the poe fear and story . a the victim and france ( play very well by laila robin ) be seal in a wooden coffin cover with dirt somewhere apparently so isolated nobody near can hear her dog insistent barking . her fear be palpable and come across with brutal reality . you hope she will survive but the outcome be questionable a time tick agonizingly slow for her but too quickly for those try to ensure her rescue . it einstein relativity theory embody in this very tense situation . on the debit side and more could have be do with her husband . his character be shunt aside too much for my taste represent what kind of relationship do they have and why be he so unaware of her darker side . an alcoholic problem be address fleetingly and but a any member of a 12 step group would know and one have to reach a base understanding of motivation to move ahead . maybe they hadn not attend enough meeting . sum up and oxygen be a surprising treat . it pull you in quickly and deal quite well with complex situation . although i shun violence and find myself want to applaud a violent act which i personally consider not to be an exception in real life .