Observed fault line in a (11-11) Gyaarah Gyaarah web series - Violation of Miranda Rights.

The interrogation scene happening in the Police station made me question, how it can be considered as evidence, Taking the statements from the accused within the police custody is clearly a fault line and not accepted in the court of law. It challenges the A20(3) of Indian Constitution. Is that so? or more to what I am missing out on.