Merlin and Arthur in “Queen of Hearts”

How did Uther know where to find you?

I don't know, you were the only person who knew where we were.

I didn't tell him.

Oh, maybe something you said gave it away.

I didn't say anything.

You know, Merlin, you couldn't keep a secret if your life depended on it!

You'd be surprised!

What's that supposed to mean?

... Nothing.