Darius looked at Santi, who was now silent when Rayindra told the truth about what his second wife had done to Cilla, his biological daughter. He can tolerate whatever Santi does in this house because he thinks she is also the mistress of this house. However, if Santi dares to touch Cilla or Edric, then that means Santi is digging her own grave. Because Darius doesn't like it.
Not to mention, the intimidating look that Rayindra – his first wife who wanted justice for Cilla – gave his daughter. He knew how Rayindra was very protective of his beloved daughter. In fact, she could do anything to protect him.
"So tell me what have you done to Cilla? Don't you ever dare to cover it all up? Because I can get all this information from anyone who saw the incident in this house. Tell me, Santi."