Maybe I Should've Posted This in EoEO

[G13]

I fail to see how suffocating or smashing said mouse's head is more humane than chucking it to the piranha's alive.

That's actually the exact definition of humane.

- Marked or motivated by concern with the alleviation of suffering.

To throw it into the tank alive and fighting to stay above the water, and then later to stay away from the piranhas, that's inhumane and disgusting. If it was destined to be food, smashing its head in would have been the right thing to do for the mouse's sake.