What do you think could be the reason that horses refused to go with the hostler?

The horses were afraid of the fire, and they trusted no one. Thus, the horses were leary of going with him.

No doubt we were very foolish, but danger seemed to be all round, and there was nobody we knew to trust in, and all was strange and uncertain. The fresh air that had come in through the open door made it easier to breathe, but the rushing sound overhead grew louder, and as I looked upward through the bars of my empty rack I saw a red light flickering on the wall. Then I heard a cry of “Fire!” outside, and the old hostler quietly and quickly came in; he got one horse out, and went to another, but the flames were playing round the trapdoor, and the roaring overhead was dreadful.