While a regrettable experience, it's extremely unlikely the RCD saved your life. Being shocked by 240V domestic supply is a thing that happens all the time, and

While a regrettable experience, it's extremely unlikely the RCD saved your life. Being shocked by 240V domestic supply is a thing that happens all the time, and deaths are very rare. Usually you'd have to have current passing through your heart, as if you grabbed a hot wire with one hand and were standing barefoot in a puddle with the opposite foot. Grabbing the end of a M-M extension cord like you described would probably result in current mostly flowing through your hand a little, then to the neutral or ground conductors.