The phrase "bed down" typically means to make oneself comfortable for the night or to settle in for rest. Some antonyms for this phrase include "rise up" or "stay awake," which both suggest the opposite action of settling down. Another opposite for "bed down" could be "evacuate" or "flee," which imply a sudden departure, rather than settling in for the night. "Stay active" could also be considered an antonym, as it suggests continued movement and engagement instead of resting. Lastly, "stay alert" could be an antonym, as it implies staying awake and vigilant, rather than relaxing or sleeping.