The Tami head is clearly shown being brought down to the ground to have the light repaired per Janet's orders. When Tina and Tami are walking it is clearly back in the air above them. In the next scene the head is still on the floor so Tami could catch Louis dumping guacamole from the Tami head nose.
Tammy notices the rear door to the walkable head sculpture is open. When she enters the sculpture a creaking door sound is heard meaning she is opening a supposedly already open door.