Who feels more guilty about the snowball incident, Dunny or Percy? Explain

Dunny feels tremendous guilt over the snowball incident. In a split second, Dunstan had decided to walk in front of Mr. and Mrs. Dempster thinking that Percy would not throw the snowball out of caution. Percy, however, lacks any kind of sympathy or empathy: he doesn't care who might be at risk. He throws the snowball and hits the pregnant Mrs. Dempster.