How does Thomas find Anna shortly before the bombing in the chapter Why I'm Not Where You Are 4/12/78?
In this chapter, Thomas finds Anna in her room. She reveals that she is pregnant with their child. He is overjoyed with the news, and they talk before he leaves. He states that it is the last time he ever saw her alive. That very night, the air-raid sirens sounded, and everyone went to the shelters to prepare for a bombing they never expected to happen in Dresden.
Yet, the bombs came. After the first bombing, Thomas goes looking for Anna. On his way to Anna's house, the second bombing begins. Thomas throws himself into the nearest cellar before it is soon destroyed by the bombs. He hides in cellar after cellar. In the city, horrible sights await him. He sees people melted into pools of liquid and bodies charred beyond recognition.
As he passes the zoo, the keeper (with his eyes burnt closed) hands him a rifle, begging him to shoot all the carnivores. In his panic, Thomas ends up shooting all the animals he sees because he says that he can't tell the difference between those which are carnivores and those which aren't. Later, Thomas discovers that he was only one of four people who made it out alive from Dresden. This means that Thomas lost both Anna and his unborn child to the bombings.