Untie them?

"OH...MY....GOD, WHAT HAPPENED TO YOU TWO, don't go anywhere I'm going to call the Police"! There are 'no cameras' in the room and he knows better than to disturb a crime scene contaminating any evidence.

Robert is on hold for 20 minutes, after that he hangs up calling a buddy in the LA Police Department, "FUCK THEM ALL ACTRESSES ARE STUCK UP SNOBS AND ONLY CARE ABOUT THEMSELVES...THIS CONVERSATION NEVER HAPPENED"!

Returning he finds them still struggling against the ropes,