the road to hell is paved with good intentions. People are protective of their pets, its usually best to try and give advice but to not take action yourself without permission. It sounds like you meant well but because the animal died your roommate is going to want to place the blame on you. Weather or not it was your fault or someone elses this is a good lesson to learn.
Hope your roommate situation does not go sour because of this but if you have the cash buying another snake would go a long way to mend the relationship. Make sure you have good husbandry first !