When someone uses the phrase 'miles away', it denotes a sense of distance, both mentally and physically. Some synonyms for the phrase 'miles away' are 'far off', 'distant' or 'remote'. Another synonym is 'out of touch', which indicates that the person is not tuned in to their surroundings. Some people also use 'elsewhere' to convey the thought that the person is in a completely different mental or physical space. Additionally, 'far away' and 'away in thought' are synonyms that can be used interchangeably to refer to someone who is not present in the current situation, either mentally or physically. These synonyms are helpful in conveying a person's state of mind in a more descriptive way.