Isn’t the entire point of officers being allowed to use lethal force that their lives are in danger? Killing people remotely when you are completely safe just seems like straight up murder.
Or in the defense of another. It wouldn’t make sense for a robot to take a life to save its own, but it might make sense for it to take a life to save your mother’s.
Also, criminals will know the robots have these capabilities, too. If a barricaded suspect hears or sees a robot rummaging around, that could be interpreted as force escalation. Which may cause the criminal to react in unpredictable ways that increase risk to the public and police officers.