That seems like a distinction without a difference. If the bomb disposal robot had been remotely controlled to detonate the bomb it was carrying while standing in front of the suspect, would that be different in any ethical or legal way from a Boston Dynamics robot being remotely controlled to pull the trigger of a gun while standing in front of a suspect?

I suppose one small difference would be whether the bomb disposal robot in that situation was destroyed by the explosion it caused, since it presumably wouldn't be destroyed by shooting a gun (unless the suspect returned fire or had a dead man's switch on his own bomb). I highlight this difference not because of the ethics of sending robots to their "deaths", but the minor practical consideration of whether a given robot is considered reusable, that is, able to amass a potentially unlimited number of kills.