Former-marine then-police officer Stephen Mader in W. VA arrives at a scene where an armed man has threatened suicide. He falls back on his marine training to perform a full threat assessment of the person and decides from his body language (most especially the fact that he's pointing his gun at the ground) and words ("just shoot me") that the man is not actually a threat and is just trying to perform suicide by cop.
Rather than shooting to kill he tries to de-escalate the situation with soothing words and whatnot like he was taught in the marines, but unfortunately two other cops arrive and immediately shoot the man to death.
At this time they discover that the gun was not loaded, vindicating Mader's assessment that the man was not a danger. Mader was fired for not immediately eliminating a threat and thus endangering fellow officers.
This is another blatant example of something that has come up a lot, scenarios that show that that the reason many police departments are the way they are is that there aren't any/many "good cops", there are "bad cops" and there are "neutral cops" that don't disrupt the bad cops behavior to the extent they should. Good cops are drummed out one way or the other, or turned into neutral cops as their idealism wears away.
In this case Mader was on probation--the article doesn't say but I assume that he's a recent hire--so it was simple for them to just fire him and be done with it.