Whether you live in a house or an apartment you can make a safe room so that if there is ever an intruder pr intruders you and or others in the home can go to the safe room and wait for the intruders to leave or help to arrive. A safe room can be made in any thing from a closet to a room you build in the basement or garage. You would not want any other way into this room. So no windows or other doors. It would probably be a good idea to keep a fully charged cell phone in the safe room at all times.
If you are hurrying to get in the safe room due to an intruder you are probably not going to have time to hunt down your cell phone, especially if you have kids that you need to get into the safe room. Along with food and water among other things to be kept in the safe room at all times. The Organic Prepper has a lot of advice and instructions for making your safe room. Everything from what type of doors to how to reinforce walls are covered.
I liked his idea of having a keypad access to the room so that as each person gets there they can go in and re-lock the door without having to worry about how the rest of the family will get in. Very thorough article that has loads of advice for any one that would like to make a safe room.