Well, if you add your priming sugar to it now, you'll have to stir it up. So, not only will you have to take the lid off (which isn't really a problem) but you'll stir up everything that settled out during your secondary (which is the real issue). If you have a free container, you can carefully, VERY carefully rack it to that container. Then after cleaning and sanitizing your bottling bucket again you can rack it back onto your priming sugar and bottle.
Next time you need to free up a fermenter and all you have is your bottling bucket, you oughta pick up a new fermenter.