Emergency services are given a location code from a control centre- (staff shouldn't dial 999 except for BTP as controllers call direct to ambulance or fire control rooms) as well as the station name. They then go to that point (such as outside 17 High Street) Some stations will have more than one place and this will depend on where a vehicle is coming from or where the person is in the station. the emergency services will be met by LU staff at that point.
The Control Centre may well do this, but the general public will not. Those unfamiliar with the system may be unaware that there is another station nearby with the same name; the line may be bad; or the caller under some stress. In any of these circumstances, confusion is clearly a possibility.