Question about a specific scene in S8E16

Hey everyone, I'm watching S8E16 and trying to wrap my head around the logic in the scene where Aiden confronts Sam about the encrypted phone network.

From what I can piece together:

• Aiden asks Sam how he knew about the encrypted phones then

• Sam admits that Monica is the one who told him about the breach.

But then Monica traps him by arguing: even if she told him, why didn't Sam report that information straight up to Aiden?

Here is what I don't get: if Monica was the one who leaked that info to Sam, why couldn't Sam defend himself by saying she tipped him off? Was it because admitting he was taking private tips from Monica behind Aiden's back would get him in trouble for running side-deals, or is there another reason why his silence made him look guilty? And why didn't Sam tell his boss about the breach of the phone network?

If anyone can break down how this logic trap actually works, I'd really appreciate it!

I tried asking AI but it just makes things up that aren't true and didn't happen.