I didn't see any threads involving this, so figured I'd ask this.

I originally played this game decades ago, and there was always something that bugged me about it. In the sickbay level after the Etherian mission, there's a terminal in the back corner that when you interact with it gives you a vocal "Access Granted" message. I've never actually known what this does, though, or what it unlocks. Does anyone have any insight?

If I recall correctly, this unlocks a nearby drawer containing a tricorder and a hypospray (two unfinished items that otherwise can only be obtained using console commands). After using it, you can use the drawer, which will open to reveal the two items.

See this section of the Elite Force page on The Cutting Room Floor (a site documenting cut content in video games).

Edit: the forum seems to be having some trouble parsing the URL within the link above (perhaps because it contains a colon). Here it is without the leading https for ease of copying:
tcrf.net/Star_Trek_Voyager:_Elite_Force#Obtainable_Tricorder_and_Hypospray