They had the criminal cornered and we're trying to negotiate/wait out the standoff without use of force. Sending the dog in is a use of force which Monday morning quarterbacks are going to second guess and cry "police brutality" about as loudly and petulantly as they do when a criminal is shot by police.  Law enforcement is only going to be sued for violating due process through the use of excessive force so many times before they stop using force as a tool in apprehending suspects.  They will, instead, wait for the suspect to do something really stupid (like fire a gun at officers or ram police cruisers) and then proceed to save the taxpayers the cost of a trial and incarceration.