the UNDERGROUND unit have found
oscillations on the seismograph.
Money Heist Season 1, Episode 11
Bring me an expert who knows
every stone UNDERGROUND.
Money Heist Season 3, Episode 8
bring in the UNDERGROUND teams
Money Heist Season 3, Episode 5
even in the UNDERGROUND ventilation ducts.
Money Heist Season 1, Episode 11
I will not hide UNDERGROUND.
Game of Thrones Season 8, Episode 2