A statement made by a defendant during an examination or trial on the defendant's incompetency, the testimony of an expert based on that statement, and evidence obtained as a result of that statement may not be admitted in evidence against the defendant in any criminal proceeding, other than at:
(1) a trial on the defendant's incompetency; or
(2) any proceeding at which the defendant first introduces into evidence a statement, testimony, or evidence described by this article.