What do you do when a penguin jumps in your boat? Snap a photo of the penguin if the boat is landed. If you are in the boat and a leopard seal is chasing the penguin, toss the penguin back into the water—FAST! You don't want a hungry leopard seal in the boat. The seal will grab the penguin by its feet and smack it around until it's dead.
Leopard seals supposedly perform some fancy flipping maneuver that effectively skins the penguin, but I've also read the seal simply keeps flailing the penguin until it gets ripped into eatable pieces. The prospect of such a gruesome death is probably why a penguin flees so fast and will take the opportunity to jump into a Zodiac if it happens to be around. The Adelie penguin in this photo is just curious. No one chasing him. (Photo courtesy of Polar Star expedition staff.)