Is life cruel? I hate witnessing vunerable creatures die in front of me.

I was on my way home and while staring on something I saw a rat barely alive looked being pour with boiling water or poisoned. I only saw it head titled a bit but it still moving its head.

I feel sad while staring it because none of us chose to live. No one wants to live as vermin. No one would wanted a horrible life. Neither animals. I guess animal kingdom is very brutal to thrive to survive.

I just cannot stand the cruelty. I wish I have power to stop it.