Because that's how long it took the police to show up at this womans house when she called 911. Fortunately the woman and her children were not harmed and the intruder in her house was caught by police. Still, she's incredibly lucky.
The guy tried to get into the room that she was in and gave up. He was a thief looking for something easy to steal. 8 minutes is a long time when someones in your house, and what would she have done if he had opened the door?
I would try my hardest to fill the intruder with holes, but maybe I'm crazy.