蛰 (insect lying still) plus 伏 (to crouch / lie face-down) = an insect curled up underground. The literal hibernation image extends naturally to a person who keeps a low profile and waits.
culture
蛰 is the same character as in 惊蛰 (jīngzhé), the solar term 'Awakening of Insects' around March 5–6 — when the spring thunder is said to rouse hibernating creatures.