Quite a while ago watched a video from IB where the person who was speaking told that you can ask the broker to setup your "liquidation" policy in the event of a margin call. My questions is that if is not the positions that are losing more money?
No margin call is when your account doesn't have enough money to cover the loss from your open position anymore. And since you borrowed money from the broker via margin to open your position, then if you want to keep your position open, then you would need to put in more money. The margin call is to notify you to put in more money. If you don't, your position will be closed.