In Chapter 19, towards the end of Lois Lowry's The Giver, Jonas is shown a video of his father in which his father had to choose between two newborn twins. His father chooses the larger of the two twins to be nurtured by the community and dubs the other a "shrimp!" Jonas then watches as his father takes out a syringe, fills it with clear liquid, and then injects the liquid into the shrimp-sized newborn's head. Jonas then realizes that his father had killed the smaller twin and watches as his father disposes of the child's body down a trash chute. It's at this moment Jonas truly understands exactly what it means to be "released"; it means to be killed by lethal injection.
It's at this moment in the story when he truly begins questioning the beneficence of the society around him. He further questions how a society can be so willing to do so much harm. We especially see these questions enter his mind when he mocks the Giver's assistant for being so willing to help. In his mocking, Jonas mimics what her responses would be if she really knew what she was doing:
I do whatever you like, sir. I will kill people, sir. Old people? Small newborn people? I'd be happy to kill them, sir. (p. 152-53)
In his questioning, he also realizes his father had lied to him when his father explained to him the ceremony. Realizing his father is capable of lying, Jonas next wonders who else has lied to him and poses the difficult question to the Giver, "Do you [it] lie to me too?" (p. 153). Finally, he asks himself, "What should I do?" because he knows full well he can't bring himself to either go back to his family or his community (p. 154).