How Lonni gets Caught

There will be an ISB Investigation lead by Dedra into the exfiltration of Mon Mothma from the senate building.

They know someone was assisting her who killed the ISB mole in Bail Organa's extraction team and Kloris.

Security footage (surely a senate building has surveillance cameras) will show that the unknown assistant was Andor and he was not part of Organa's extraction team, which they already knew about, but a backup one.

That will tell the ISB that the people helping Mon Mothma knew that Organa's extraction team was corrupted and not to be trusted, and sent another one to intercept her beforehand.

Who leaked the info about the ISB field agent? This agent was under Lonni's supervision. Larget only stepped in to assist in Lonni's absence.

Suspicions will be raised about Lonni's division. Agents will be sent to tail Lonni and his subordinates to find the mole.

I think we know where this goes.

Suspicions are raised