>>Does that really mean that the account will be crashed with 4 consecutive losses?<<

No. Dependent on open trades and slippage, you can theoretically crash your account with 1, 2, 3, or any number of consecutive losses. The Margin slider determines only the average margin, the margin of individual trades can be higher or lower. And the Risk slider determines not the max loss per trade, but the risk limit, i.e. the loss of the worst trade.