We are all sinners, and we need the sacraments of the Church to restore us to Sanctifying grace. If those sacraments are destroyed, your only hope is to have a perfect act of contrition.
So, yes, it is possible to save your soul and be restored to the true church, but not easy and a gamble for sure. Better to keep the Faith and rely on the Sacraments of the Church to help us if we need them.
Remember these people are being brain washed to believe that all men are saved, do you even think they worry about it.