It is quite possible the Fire Authority insisted on the fire door being installed - & they must open outwards.
On the other hand, it may be that the shop owner/lessee has done it because of their own concern about escape.
Either way, I doubt there is anything you can do about it except possibly see if they will put a reinforced glass panel (has to comply with fire regulations) in the door so they can see if anyone is passing before opening it.
However, I do think you are worrying unnecessarily - the chances of them happening to open the door just when you are passing must be very remote. There are plenty of examples of outward opening doors in all sorts of situations which don't seem to cause problems.