When the team gets the Bandium app alert in the bullpen, the closeup shown on Agent Knight's phone indicates the message is from Agent Parker. However, Agent Parker is also present and gets the alert at the same time as the rest of the team. Therefore, Parker could not have sent the Bandium message.
The actress comes from the parking lot and goes into the elevator unattended. She is also left in the office without an agent watching over her, plus she is not wearing visitor pass. In reality no one that was not a NCIS employee would be allowed in building unattended let alone without a visitors pass, as this is a major security breech.