Though I understand the general idea you are trying to communicate.

My question is how in the hell did this situation get extremely hot all of the sudden instead of smoldering discontent we have had for years.

We went from (this is a simplistic summary)

1) An authoritarian dictator who was the front man to the military (Mubarak).
2) Young people (Tahrir Square) wanting change, these people were not particularly religious.
3) The military who ran Egypt for decades, decide to meet the protests somewhat with getting rid of the dictator as a show of good will and moving to a new form of power sharing with a constitution and elections.
4) The Muslim Brotherhood wins half of parliament, later on Mohamed Morsi (connected to the Muslim Brotherhood) is elected president. Morsi spends the next year trying to expand Muslim Brotherhood power while at the same time dismantle old power structure connected to the miliary.
5) During all this time the economy of Egypt is tanking, we start to see protests over Morsi (people that can't eat take to the streets). Eventually it ends with a week long struggle where the military throws out Morsi.
6) We had 6 weeks of protests by the Muslim Brotherhood. There were some deaths but each individual incident the death total was less than 100.
7) The interm president declares martial law for a month and that same day protests are broken up and over 500 are killed.

What changed in the last week that caused the military to take deadly action?