Elementalist
Depends on how clear you make it to the readers that the child will be unharmed because the child's caretaker will act.
If it's unclear, then I guess it might be going too far. And even if it isn't, it will most likely make the protagonist look like an utter jerk.
Just before throwing out the real baby, swap it out for a baby doll.
Why does the aunt have to be forced to save the baby, by the way?
edited 30th Dec '15 6:55:21 AM by hellomoto
@ hellomoto: The aunt was forced to save the baby because she was partners with the protagonist and they disagreed about some decisions he was making. Knowing she's far stronger physically than he is, he forces her to save her nephew or watch him die, giving him time to carry out his plans without interference.
edited 31st Dec '15 6:22:41 PM by Swordofknowledge
Fear is a tyrant and a despot, more terrible than the rack, more potent than the snake. — Edgar Walllace
Elementalist
Preparations for a pretend death that would force someone to save the target usually take more time than actually saving said target.
So you might want to ask yourself, when would he have the time that he'd be free to use for this but not for his plans?
I'd say just go for it. Or if there's a snippet leading up to it, post it so we have more to go on.
Long story short, I'm thinking of having my protagonist toss a baby off a high building in order to force his aunt to leap off to try and save him.
The action is cruel and callous, but he deems it necessary. What I'm wondering is if this is perhaps too much. His actions are the culmination of a steady downward moral spiral, but I want him to keep his head above the water so to speak. I don't want a Villain Protagonist on my hands.
Note: the baby in question is a vampire, as is the aunt—but in the context of this story they aren't undead, just a predatory subspecies of humans.
Fear is a tyrant and a despot, more terrible than the rack, more potent than the snake. — Edgar Walllace