The priest realised that he'd left his tackle box in his car, and, not wanting to disturb the other two, got out of the boat and walked over the water to the shore, got his gear, walked back, and started fishing.
An hour or so passed, and the bishop began to feel a little hungry. His lunch was back in his car, though... so, he got out of the boat, walked over the water, got his lunch, came back, and nibbled on his sandwich.
The evangelist, not to be outdone, decided that he'd best go for a walk, too. He mumbled something about going to the bathroom, stood up, stepped over the side of the boat... and splashed into the lake.
The priest, chuckling, said to the bishop "Think we should've told him about those submerged rocks?"
Said the bishop
Spoiler:
