If the bed's a-rockin', that's usually a good thing. When it's a bad thing (i.e. amidst a natural disaster), you have two choices: 1) Be crushed by whatever falls on you or 2) Drop into the handy survivalist bunker built into the bed, shown above and featured in the video below.
Whether you're sleeping or otherwise engaged, naturally it'd be jarring to be quickly swallowed into the pit of your bed. But hey, at least it's much less scary-looking than the potentially limb-severing devices depicted in this animation. (What's up with the freakily upbeat organ music?)
Assuming the bed produces a minimum of false positives (no earthquake, but drops you) and negatives (doesn't drop you when it should), it seems like a good concept. Especially given the unpredictability and number of earthquakes, as pointed out in the above video.
Of course, water and food bars may get you far; but just the same, you should probably also have a survival kit nearby, not to mention a reliable escape from your building. Also, what happens when the ceiling collapses on top of you, entombed in this bed, and you're stuck there for all eternity?