>>282003621
You may be remembering the end of season 3, where they freaked out the first time they heard why man's "12 million meter" command. But fortuantely the medusa was across the room when the radio played the message, and they realized that the audio source has to be really close for it to work.

that was like the first and only time they mentioned that limitation of activating the medusa, until magma's comic relief moment they cut from this episode