The army should not suppress the Brotherhood. Doing that will only make martyrs of them. Call elections in a few months and let the Brotherhood be rejected by the people.
Which people?
Substitute Nazi or KKK or Maoists for Muslim Brotherhood and think about how allowing them to campaign is a good idea.
Sometimes decent people just have to take out the trash that is stinking up the place.
A few dozen dead MB would be martyrs ;a few ten thousands dead would be an Egyptian housecleaning just like the King of Jordan was forced to do back in the 60s/70s, else the scum take over that nation.