Poor lady, living in fear of rats going to the trouble of climbing up the house wall and getting into her bedroom during the night!
They may say that no matter where we live, town or country, we are always less than 10ft away from a rat - can I ask how many of us have seen one? I live on a farm and seldom see one unless I go specially looking.
Rats have better things to do with their time than terrorising humans in their beds. Food is their top priority so they'd be heading for your kitchen, not your bedroom, if they take the trouble to invade your house.
If you're really worried get some of that mesh that let's the air through and stick it round your open window and try to stop worrying. Mr Rat is terrified of you and won't come near you unless he's desperate and you have food in your bedroom. Please don't let this lady scare you into losing sleep.