What Does The World Outside Look Like
With a single leap, he covered the distance leading to the top of the tunnel and found his way out of it. As for Dana and Nadea, he left them behind under the excuse of not being their babysitter.
Having no intention of killing them is not the same thing as sparing their lives. He just doesn't want to directly have the blood of a child on his hands, even though he did directly kill Tarja, the baby bear he had rescued.
That was a situation that could not be avoided as it was the only way he could rid himself of the Goblin king. Besides, he was but an infant when he found himself in the Dungeon. As children with looks putting them above the infant range, he is certain they will make it out alive. And if they don't?...., well, he did the best he could.