This was actually a hint to the others that going back to pick up people was a risky affair. Most people inherently possess a self-serving nature, and once everyone was aware of this, should they decide not to return for the pickup, the voices of opposition would be much reduced.
When Fabian and his group first followed Robinson William as they left, they were puzzled as to why William didn't issue a gag order to the others as he had when they first boarded the plane, but by the time they reached the Conference Room, they had already figured out the reason and so their expressions turned somewhat awkward.
A somewhat silent group entered the Conference Room, and William took the initiative to close the door before he directly began, "I presume you are all aware that the reason we left in a hurry was actually to verify the stories that Madeline told during the meeting."
