The guards, when getting the Prince's urgent summons, had quickly escorted Riku (because at least one of them was always within ear shot of him) to the Princess and left him with her and her guard for safe keeping.
So, at least one Trabian had arrived. Philip was sure he'd hear more while he showed this man around. "Yes, Your Majesty. Sir Lafet, Captain Barkley, please follow me." Really, he was just there to assign a path to take while the other two talked.
Frank looked over at the Prince once the three men and boy had left the throne room with the Prince's permission. Oh how he wanted to ask about the Trabians! "Any further orders, Your Majesty?"