How many times have you been in the middle of a conversation with another person and the subject changes, but your mind keeps circling around what you had planned to say next?
How many times have you planned on doing something like taking a hot bath, only for a phone call or a chore you kept forgetting to do pops up?
You don’t stop thinking about what you wanted to say even though the moment in time to say it has passed.
You go to bed thinking about that relaxing bath you meant to take but ran out of time.
Don’t forget this happens to everybody–even your characters. what we think about, what we desired, it means something–even if it is just to us, and these can be motivating factors for your characters even as they are forced to respond to outside forces, there inner monologue still yearns for what they’d intended.
Remember to position your characters in the direction they want to go before that direction is altered for the sake of the story, and keep in mind that they probably haven’t forgotten what they meant to say or do.