Sec. 5. Nothing in this article precludes the admission of a statement made by the accused in open court at his trial, before a grand jury, or at an examining trial in compliance with Articles 16.03 and 16.04 of this code, or of a statement that is the res gestae of the arrest or of the offense, or of a statement that does not stem from custodial interrogation, or of a voluntary statement, whether or not the result of custodial interrogation, that has a bearing upon the credibility of the accused as a witness, or of any other statement that may be admissible under law.