While the SLPD is off playing whack-a-mole up in O’Fallon Park (“hotspot policing”), this leaves all the other slightly less “hot” spots “mysteriously” lacking in cops. Which means it’s every man and woman for him or her self.
She lives on a third floor, which means these three “men” wanted to go into her apartment and hers in particular for some reason. We know that because they were going up an outdoor staircase to the third floor. It would seem that one or more of the three already knew her for some reason, and knew what she had to steal.