Kicking the door in is surprisingly easy in the US where most doors are framed in soft pine, if that does not work an angle grinder and a sufficient supply of discs can (eventually) cut through anything.
It doesn't really matter whether a locksmith can open your door. With an angle grinder and some patience, anyone can open practically any residential door (as noted by another commenter). The question then simply becomes how expensive it will be to repair everything afterwards -- and all because the battery ran out.