I don't think anybody here is advocating that you bend over and touch your toes if there's an intrusion. You should arm yourself and, if circumstances permit, gather the family. Only then do you hunker down, call 911, and blast the hell out of the BG if he comes into the room where you are. Leave the "room clearing" to the professionals unless there is no other choice.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.