its called disassociative shock. when confronted with a traumatic situation that is so outside of the norm and psychologically overwhelming, people often disassociate and their mind goes somewhere else. you brain just splits off so your conscious self doesn't have to register the trauma. you become passive and thoughtless.
oftentimes this is followed by dissassociative amnesia, ptsd or somatization - people will start suffering from vague pains with no physiological cause (there are cases of people going blind after experiencing trauma - when nothing was actually wrong with their eyes at all). vaginismus for example, which is when a womans vagina contracts whenever any kind of penetration is about to occur, is oftentimes as a result of a previous traumatic sexual experience.
the other thing that happens in some cases, is that a woman, when put in such a situation, will make a conscious decision to just go along with what is happening, in order to avoid a graver ending. if someones trying to rape you and you dont think you would be able to get away if you fought, or you think that if you resist it could become worse, it makes sense to just submit in order to get it over with faster.
i saw in some comments on some article, a person was questioning why only years later people come forward about abuses that have happened in the past. its pretty much because of dissassociative shock - after the event, the person will compartmentalize the experience in the subconscious so they dont have to process it. then maybe they get some somatic illness, or ptsd, or they just act out and they dont know why. it takes many years but eventually those compartmentalized/split off memories resurface in the conscious mind, and at that time the person is forced to process what happened.
dissasociative shock is the underlying factor in people who suffer from dissassociative identity disorder - multiple and repeated severe psychological trauma will sometimes split a person so much that they develop other personalities to help them cope with what they have gone through. but thats on the extreme end.
-source: nursing school/dsm IV/personal experience