Hm... I think its reasonable for certain jobs to be exempt or limited as Lovely has suggested. I mean female bus drivers, teachers, nurses, doctors, politicians, train drivers, pilots, serving soldiers in battle... If any female can be raped at any time without question there is going to be a stack of problems, even to the point of people dying or missing vital appointments/connecting flights and such. So if Lovely's nurse is attending a patient and its urgent then I think certainly she should be in her rights to refuse.
I think there needs to be some sort of limit to how much any man can impose on a woman here.
Maybe never while a woman is at her place of employment and working. There. That covers it quite well I think.
An alternative is a whole quantum-shift in society so that women no longer have 'critical' jobs and they work only in places where constant interruptions are not going to result in something bad happening such as someone dying. So a nurse would be excluded for that reason, nurses would be male. That too could be a possibility.