You had better march straight back out the way you came.
3 seconds sound clip from the The Secret of NIMH (1982) movie soundboard.
You can hear this line at 00:37:34.919 in the Blu-ray version of the movie.
Quote context
[...]
- It's me.
- What are you... What are you doing here?
- Oh, thank goodness it's you.
- How in thunder did you get in here?
- The plow has come early to the field.
- You had better march straight back out the way you came.
- I can't bring Timothy out. The chill in the air will kill him.
- That's another matter. That doesn't explain what you're doing here.
- And that big rat chased me away.
- But I must see Nicodemus. The Owl told me to see Nicodemus. Yes, perhaps you should...
[...]