Look at the terminals on that Speed 400 motor. Many of them come with the capacitors already installed internally. The telltale sign is a tiny wire poking through the motor terminal.

The main reason ESCs blow up is from the main battery being hooked up backwards. The next most popular cause is a short circuit. The other <1% of the time, it's because of a bad ESC.

Motors can't be hooked up backwards; they'll simply run the wrong way. Having the throttle channel reversed also wouldn't cause your problem; the ESC simply wouldn't arm.