TF,
Part of your question is easy to answer -
Lose an engine and you lose it's generator
Lose a generator, you lose the mission bus
Lose the mission bus, you lose the Police radios.
Even if the SHED Bus switch had been activated, which it wasn't, it still takes around 40 secs for the Airwave head to fully re-boot.
Prior to the first engine quitting however, I have absolutely no idea.