The problem I have with this is the approach of looking for people ever more remotely associated with the events until you find someone with money / insurance. So the directly liable person was the killer. No money here so move on. Then you have the employer, who required the killer to be armed, may have required the killer to work excessive hours and did hold liability for vicarious acts of their employee. Now they got off because they successfully claimed that the act was not carried out in the course of employment. So move on, next it is the landlord, perhaps next the manufacturer of the door?
The other problem is that it is argued that action must be taken to protect against ever more remote risks. So we are now going to argue that all residents in communal accommodation will have to have security retrofitted to prevent a resident of the building entering the wrong apartment and opening fire on the resident. A civil lawsuit based on a rare event seems a very bad way of establishing security standards. Increased security means increased rents and maintenance costs making accommodation less available to the poor. It may make access in the event of emergency more difficult and may make deaths more likely. Electronic systems may be vulnerable to hacking. Auto-closing doors have the result you can lock yourself out then leaving you with no easy way to get back in when you are at risk e.g. from mugging and may result in an increased risk of death.
So what is the outcome, self locking doors - future court case that these are negligent; no self locking door current court case that these are negligent. Cars do not all have air bags because of tort law but because they are legally mandated. (Otherwise the cases where manufacturers were sued for harm from airbags would have resulted in them being removed!)
The US practice of punitive damages is what results in US legal costs being so high. It may be an excuse for not having appropriate regulatory frameworks because safety is left to tort law. The appropriate place for someone to be punished is not a civil court but a criminal court with appropriate legislation e.g. health and safety. The civil courts can level 'fines' far greater than the criminal law would allow on far flimsier evidence. These fines from civil cases can then be converted into prison time if the person cannot pay the 'fine'.
