Any other experiences with bitcoin beveren ? need advice for bonus

i used the bitcoin beveren roulette only 2 times so far. the first one i lost around 1 bitcoin and now i have won 4 bitcoins and i havee also a bonus added to my account so i am not sure if i should play or withdraw. if i withdraw i lose the bonus… what is smarter to do?

edit: sorry i forgot to show this is the bitcoin roulette: Bitcoin Beveren