I think he just wanted to make sure that the pond was still there, because he came back in a few minutes from the other side of the house. In his mind, he came back. In your mind he took his sweet time, ignored your pleas, ran off without permission and generally exercised his own will, instead of yours. I have to be very careful when I discipline him because of his running off. If he eventually comes back to me, I'll usually just let him know how displeased I am with him.
Guilt is enough.
I'll really let him have it. Otter is learning to fly. Otter has of late become very concerned whenever I cook. He'll stay in the bathroom, without making a sound, until we notice he's missing and let him out. Otter at 15 months.