Basically, Benedict waits until the real police show up, at which point he reports Danny and files a police report.
Why? Because Benedict just got robbed, and he'll need to go to the police in order to file a police report, which is almost certainly a requirement before cashing in on insurance for stolen money. Presumably, the REAL POLICE showed up when they called 911 (since Livingston is now in SWAT mode and can't block the call), and the casino (and Benedict) waited until the REAL COPS showed up. Danny was 'presumably' in the locked room with the big guy the 'whole night.' When he was finally 'released' and facing Benedict, he offered up lightweight info in exchange for Benedict giving up Tess - at which point Benedict reports him for violating his parole.
