From "Star Trek: Voyager: Message in a Bottle (#4.14)"
How did you manage to release the neurozine? I never opened the ventilation system.
Trapped in the Jefferies tube, alone, nowhere to run. His smug comrade captured by Romulans. EMH Mark II had to improvise. Inspiration! He accessed the main computer and simulated a ship-wide bio-hazard, making the computer think there was a micro-biotic contamination on all decks.
] And the ventilation system opened automatically.
Presto! He then crawled back out of the tube, accessed the holo-emitters, transferred here, excused the Romulan, saw the dumbfounded look on his comrade's face...