I flew on LOT (Polish Airlines) recently and during the safety demo all flight attendants (I saw 3 or 4 down the aisle) removed their masks and kept them off fo

I flew on LOT (Polish Airlines) recently and during the safety demo all flight attendants (I saw 3 or 4 down the aisle) removed their masks and kept them off for several minutes. Why? You can't demonstrate the oxygen mask dropping down while you're wearing a mask yourself?