Snorting something like morphine is a waste, in my opinion. There really is no rush. It's just a faster onset, 10 minutes versus 45 minutes. But for what? If you're taking say 60mgs, it's only going to feel like a 45mg or so morphine high. The peak will be short. The duration will be short.
You could get a lot more out of them taking them orally.
Also note that the time release mechanism on MS Contin is extremely effective. Whatever the process to creating it is, the TR compounds stay tightly binded to the morphine molecules. This means that even if you crush it very well, if you take it orally the effects will still last a good 8 hours.. maybe more. Just lightly chewing them will provide about a 12 hour high if the dose is large enough.
Also also note that there was a thread about MS Contin not even two weeks ago. There's a reason why this board has a search engine.