As you get to know your characters, you understand how they’ll behave in any given situation. Perhaps your character would never lie, or be judgmental, or steal. But when backed into a corner, we can all act out of character. And bad behavior is a delicious source of conflict and trouble in a story.
Think about your character’s moral code. What are five things they swear they would never do?
Now, write a scene where your character is backed into a corner and breaks their own moral code. What pushes them into it? What are the repercussions? How do they feel once they realize what they’ve done?