This is how Mac talks to Astrid goes in The Impending Duel.
[Then we see Astrid and Stormfly in the stables]
Astrid Hofferson: I'm sorry, girl. It's just that when it was time to fight Grindelwald, I hesitated, and you got hurt.
[The flashback begins with Astrid hesitating to fight Grindelwald]
Astrid Hofferson: It's not too late to change your ways.
Gellert Grindelwald: You're so native that you would seek to save me rather than destroy me?
[The flashback ends]
Astrid Hofferson: I can't afford to let my feelings get in the way of our mission again. And I won't.
[She then sees a Terror Mail and reads it]
[We cut to the clubhouse]
Astrid Hofferson: Mac, it's crazy to do this. Take on Mesogog and do it alone?
Mac Grimborn: Mesogog insists how it's gonna be.
Astrid Hofferson: [realizing that Mac is right] I know now that Mesogog won't stop until you duel him, and hesitating would be a mistake. You have to go.
Mac Grimborn: I don't have a choice but to fight Mesogog. I'm ready for this battle.