How do experienced Buddhists preserve their equanimity and well-being in unfavourable circumstances?

What are the examples in ancient texts or in history when a trained Buddhist sustained their equanimity and well-being through torture, forced isolation or other unfavourable circumstances? Which tools given in Dhamma do you think would be useful if one had to survive, for example, through the years in prison? Could it be possible to keep on the development of skilful qualities in places like this? Would you consider suicide as a solution?