How does Vladek survive the work camp? What motivated him?

Though it is cold, Vladek goes to the river every morning to bathe so as to keep away the lice that attacked so many of his comrades. To pass the time, he does gymnastics, plays chess, and prays. Vladek wakes up one morning to find a sign requesting workers and advertising good food and accommodation. He volunteers, and when he arrives at the camp, he is given his own bed and a full day to rest.