Yes, this happens very easily. Pills aren't bulletproof. If they are shaken around a container enough, or grind against eachother enough times, then they can surely turn to powder.
Is it safe? Well, is any pill 'safe' to take? You'll never know until you test it. But the most I can tell you is that the ingredients aren't going to change from the pill being broken up, unless something else was added to the mixture later.
Remember that pressed pills do have binders and fillers in them, as well as MDMA or adulterants.
With the powder, you can either put it into gel caps, parachute it, or administer nasally/rectally. Use a scale if you want accurate results, but if you plan on eye-balling the dosage.. be careful. Maybe try getting ahold of some smaller size gel caps to fill, just to be on the safe side. You can always redose.