[They were worried? He didn't want to worry anyone...]

I thought you would be angry... I didn't want to worry anyone, I'm sorry.

[He knows that, kind of, during those ten days Ryoga getting lost was kind of a constant worry but they were used to it so it didn't matter much. Still he worries.]

B-But it's not good to be lost! It's not nice and you're alone! I'll go find you!

[Or try to.]