Let me go on record to say that taking out the assassin in Dallas with a robot bomb was an astonishingly good command decision to end the standoff with a militarily trained sniper who shot over a dozen citizens (including executing 5 police officers) so he couldn't shoot or execute more citizens. Two hours of negotiations proved to be fruitless.
Akin to a military situation, the commander, in order to suppress casualties, took the strongpoint out with artillery rather than expose those advancing upon the it to harm due to their inadequate protection and cover. And I don't think the robot pinned the assassin to the ground then shot him.
Rather the robot went into the killer's liar and blew itself up, which killed the barricaded cowardly murderer. Yay.
(From a former police officer.)