pkpk was crying last night and now her eyes are swelled up.  Tears are strange; you cry when you're happy and when you're sad.  This discussion of tears reveals a terrifying plot!
Those are tears of guilt 
from cutting up an onion.
Esas son lágrimas de culpabilidad por cortar una cebolla.
Son lágrimas de culpabilidad por cortar una cebolla.
Essas são lágrimas de
 culpa por cortar a cebola.