this is a bit long winded but it is a complicated film i hope it is explained well if something dont sound right let me know.
it starts off in an old bathroom type thing which turns out to be in an old sewage works.
there are two guys chained to pipes at oppisite sides of the room with a guy shot dead in the middle of the room. they retrieve the tape player from there hands and listen to there own tapes that say the doctor has to kill the photographer who has been following him and taking pics of the odcs suspected affair. the doc has been given a bullet and has to take the gun from the dead mans hand he has to kill the photographer by six or docs kid and wife are going to be killed.
they work out that they are being filmed and doc figures out that it is a bloke called seth that works in same hospital with him that is holding docs family hostage.
doc does not shoot photographer but docs with and kid have managed to escape and so seth goes to kill doc. but doc has listened to the wife struggle with seth and thinks that she will be dead so having been given saws at the start the doc then saws off his own foot(yuk).
photgragher manages to kill seth by hittng him on the head repeatedly with cistern top. doc trys to leave the room crawling to get help leaving photographer chained to the pipe with two dead people in the room.
when doc leave photographer finds a tape on seth and realises he is not the killer but was told to do what he was doing by the real killer to save his own life.
the supposed dead man the stands up pulls of his mask(there to make him look dead) walks over to the door says' game over' and shuts the door behind him.
During this it shows how in rather gruesome ways the bloke managed to put others in positions where they died awfully but he never actually killed them.
its hard to explain.
but the doc was once a suspect for the killings as his pen was found at one of the crime scenes.
A copper who still suspects him is the one who saves his wife and childs life but then loses his own trying to follow seth to the sewage works.