Semi-pessimistic assumption: Harry is in the Mirror, which has staged this conflict (perhaps on favorable terms) because it’s stuck on the problem of figuring out what Tom Riddle’s ideal world is.
Pessimistic assumption: Voldemort evaded the Mirror, and is watching every trick Harry’s coming up with to use against his reflection.
Semi-pessimistic assumption: Harry is in the Mirror, which has staged this conflict (perhaps on favorable terms) because it’s stuck on the problem of figuring out what Tom Riddle’s ideal world is.
Pessimistic assumption: Voldemort evaded the Mirror, and is watching every trick Harry’s coming up with to use against his reflection.