Lin Xian still couldn't understand what the phrase "The mirror holds what you desire" truly meant.
Because conventionally,
a mirror is simply a flat structure that reflects light. As long as the surface of an object is smooth enough, copper, iron, plastic, ice, or even water can all become mirrors.
In modern society, glass mirrors are the most commonly used, affordable and practical. Every household is inseparable from mirrors, whether in the bathroom, in the wardrobe, or even on the mistress's vanity table, a mirror is indispensable.
Lin Xian looked into mirrors many times a day, both intentionally and unintentionally.
He didn't find anything special about it each time he did.
Moreover...
Based on the construction and physical principles of mirrors, "inside the mirror" is a concept that doesn't exist.
A mirror is just a mirror, a thin layer of glass, it doesn't have an inside.