@mysteryman,
Orcas are very intelligent, like all dolphins (btw, they're just large dolphins, not whales) and love to play with humans and dogs. They've never been known to kill either man or dog for the purpose of eating them; perhaps we're just too bony for them, unlike seals. Besides - look at the dog! If he felt threatened by the dolphin in any way he wouldn't be standing there rubbing noses with him.
The only known case of an orca killing a human involved an orca who had been kept in a water tank and abused by his trainer - and even then, the dolphin simply held the man underwater until he drowned.