Death of compassion

We(V and myself), are having one of those nocturnal, before drifting off to sleep conversations. Suddenly he sits up, fake fear et all, points to the entrance of the room and says " Aaahhh..a dog is running towards us"

--By now, i am used to his imagination and cooly respond from my splayed out posture " Don't worry kanna, amma will shoo it away"
--V says " No Amma, wait". He then proceeds to roll up the handtowel he carries to bed, makes a gun, and aims to shoot the dog. " There, once i shoot the dog we can go to sleep without worrying".

I am not exactly the poster girl for non- violence, but something about his calm demeanour nags me. But, instead of launching into a sermon, i decide a different take.

--I tell him" Don't shoot it kanna. The dog's mom and dad will be coming behind it. They will be very sad and cry if you shoot their son".
--He pauses for the minute, raises his fake gun and shoots anyway. He then turns and tells me " Don't worry, i have shot the dad and mom also, now they will not cry"

Someone please tell me i missed the memo on " Death of compassion"!!!!!