Many shots are from Gilligan's POV, yet no one looks directly into the camera when they are shown doubled/quadrupled or upside down while talking to him.
When Gilligan is seeing things upside down, he looks at his watch and says "I can't tell if its quarter to three or half past nine." Quarter to three upside down would be closer to quarter past nine. And half past nine upside down would be closer to three o'clock.
Since the Captibora berry extract was meant to be an antidote for Gilligan's upside down/multiple images vision, drinking it should not cause the headhunters to experience those same problems with their eyesight.