At the part where the group falls out of the boat, and go inside to dress, there is only a short amount of time for the children to remove wet clothes, dry, change into their better clothes, go to Baroness Shrader, speak to her about singing, begin singing, and be heard. It would take several lines for the sound to reach Maria and The Captain, if at all. Yet, when he goes inside, they're all dressed and nearly dry, except for Leisel whose hair is long and therefore soaking wet? The boy next to her, Kirk I believe, his hair is almost completely dry, and not a drop of water on anyone's skin. When Maria comes in, she is completely sopping, all over and not just in the dress. In the time they had, only their clothes would be dry, for they would have to run upstairs and throw on clothes without speaking, then return and speak to Shrader. Doing all that was needed to look so dry would take three times the lines on Maria and The Captain's part.