The “radicals” are the muslims who are actually following the teachings and laws of the quran.
The “moderates” are the ones NOT following their leader and their “holy” book.
There can never be a guarantee that those who are currently not following their mandate as given in the quran, will remain that way. They could start doing what they are instructed to do at any time.
A Muslim goes to heaven if his good works outweigh his bad. It's an ill-defined calculation. But the greatest work that a Mohammedan can do for Allah is to be killed while engaging in jihad, i.e., killing kafirs (un-believer).