Rock Paper Scissors

[A father is cutting onions. Tears come out his eyes.]
Child: Daddy, why does cutting onions make you cry?
[A flashback from when the father was a young boy. A wagonload of onions has overturned, crushing the boy's father. The boy desperately tries to pull him out.]
Boy: Papa! Papa!
Papa: Run... get help! This is it... Get mama... get the priest...
[Return to the present day]
Father: Onion gas