After Negan leaves Maggie to die at the end of Part I, she narrowly survives by crawling under the train and reuniting with the group. The team is forced to fight through a train car packed with walkers, leading to several casualties among the Wardens.

(Season 11, Episode 2) of The Walking Dead concludes the intense opening arc centered on the team’s dangerous mission through a walker-infested subway tunnel and the escalating tension between Maggie and Negan. Episode Summary

The friction reaches a breaking point when Maggie prepares to kill Negan for his betrayal. Negan defends his actions, arguing he isn't a "liar" and simply chose not to help someone who intends to kill him anyway.