On the basis of the NYC case of Kitty Genovese, there is a definite basis for providing aid versus keeping the door shut.
In the case as listed above as well as the case of Kitty Genovese, with the expectation of assailants outside rushing the door, it is prudent to take measures for addressing an invasion.
I would like to think that I would take adequate preventative measures, aim to let the young woman in and immediately lock the door, but sit her on the couch and keep watch over her until the police arrive to take charge of the situation.
Talk through a window. Call the police simultaneously or first, etc.