Mouse run down the hallway and turn around and run back again ?

hi all last saturday night i saw a mouse in my hallway and im terrified .iv been living in my flat for 18 months and have seen or heard nothing until last week ,however i have those sonice repellers plugged in everywhere so i was quite surprised i saw one but the confusing thing is it ran towards where i had one plugged in and turned around and ran down my stairs i find that really odd behavour for a mouse doest it just run and hide anywhere iv never seen a mouse turn around ?? anyway i was really frightened and borrowed my neighbours cat the next day which was last sunday and i still have the cat he is adorable and great company too i think i will get one my son loves him too ...my question is this do you think the mouse is ggone and is it the cat that is keeping him out ? many thanks in advance