CAVE was an early voice encryption process (2G I believe)
http://conningtech.blogspot.com/2010/08/3gpp2-cdma-authentication.html
Cave is the Latin present imperative tense of "cavฤre" = BEWARE.
Present imperative tense is used "to give orders or commands."
sauce
https://latin.cactus2000.de/showverb.en.php?verb=cavere
https://classics.osu.edu/Undergraduate-Studies/Latin-Program/Grammar/mood
EVAC is CAVE backwards
pic from
https://www.af.mil/News/Article-Display/Article/131384/airmen-train-for-air-evac/
Fidget spinner as centrifuge separates blood plasma
https://www.eurekalert.org/pub_releases/2019-01/acs-fsa012319.php