In the first season, I believe many people wanted to know whether Tommy was dead. In fact, he was not. After being shot, Tommy was rescued. When he woke up, he found that the person who rescued him was Amy.
After Tommy learned that Gus was taken away by the last humans, he took rescue action.
But impatientAmy couldn't wait until night to save the child, and was discovered by the last human organization.
As the two ran away, Tommy dropped the toy dog in the dog food hoping that the children would know that we were coming to save them.