His quote is from page two of the article where they discuss taking water temperature measurements from the open doorway of the helicopter. (rabett.blogspot.ru)
We also do not recommend any pressure gates that do not open in both directions or do not have a walk through doorway. (babysafehomes.com)
We discovered a hidden window in the kitchen wall... which made us think: why not turn the narrow doorway into an open wall? (tatertotsandjello.com)