How would you describe Mother's reaction to Maria's overhearing her comment "we should never have let the Fury come to dinner"?

Mother is embarrassed, and she seems to be a bit nervous.

'We should never have let the Fury come to dinner,' she said. 'Some people and their determination to get ahead.' Just after she said that she turned round and Bruno could see that she had tears in her eyes, but she jumped when she saw Maria standing there, watching her. 'Maria,' she said, in a startled tone of voice. 'I thought you were in the car.' 'I was just leaving, ma'am,' said Maria. 'I didn't mean-' began Mother before shaking her head and starting again. 'I wasn't trying to suggest-'