Most police officers take their firearms home with them and they usually lock them away until the next day. They also take home their police cruisers because they are always police officers. It seems normal for them to take home their firearms and keep them with them. If a neighbor is broken into by a robber, then their police officer neighbor can run over and apprehend the robber.
However, if they did not have their firearm, they would have trouble apprehending the robber. They need their firearm at all times if they are going to perform their police duties wherever they are. They are never off duty. However, if they have children, they need to keep their firearms in a secure place in their houses.