Hmmm, pomegranates don't really squirt, it's winter in 'US right now, so watermelon would be out of season.
I'm going to go with grapefruit, because you eat it with a spoon usually, so digging in the spoon would put your eye in prime position to be squirted. Anything you taake bites out of is more likely to squirt onto the person sitting in front of you than into your own eye!
That's my theory anyway!