Is there more than one way out of her street? If it was a random person and he saw an opportunity, wouldn't he be concerned his car might be identified by neighbors? Wouldn't he be concerned that she would see a car she didn't recognize and run back in? I don't know, anything is possible.
If he were watching her for a while, he probably knew the neighbors' routines as well. Also, he wouldn't be worried if he had a 'reason' for being in the area. A phone company employee, utility worker, etc.
Also, if she saw a car she didn't recognize and just ran back in, that doesn't hurt anything. Driving in a neighborhood you aren't from isn't a crime.