Miranda is very complicated. It generally means that the person cannot be interrogated. The penalty for violating the rule is that anything said is inadmissible

Miranda is very complicated. It generally means that the person cannot be interrogated. The penalty for violating the rule is that anything said is inadmissible. That is an important difference. If, for example, the witness isnt read his Miranda rights but just chooses to say something, that is fair game because he wasnt being interrogated. (Further, this is also a simplification, the full extent of Miranda is complicated, so this is just a perhaps overly broad taste)