"Go ahead and kill it, just know the moment you make any move which isn't to depart; I will fire and you'll be joining the beast in death." Rufus replied coolly, hand holding the stone releasing the barrel of the gun to fist around the stone.

The moment the older man made his move he would fire at his head and if the fool died then he would have two of the stones it would appear. Of course there was always the option of just firing on the man now and upon his death take the stone anyway...it was a rather tempting thought that.

Justifiable as well, since the man was wanted for the death of one person already and he had broken into his house...it was obvious self-defense. He could even claim ignorance if anyone questioned him about the stones. The man must have left it elsewhere before he had come after him, obviously he didn't have it on him now.