What is the difference between killing oneself to end suffering and martyrdom as a result of defying anti-Christian authority?
The difference, and is it a major one, lies in their motives. The person who chooses to take his life is completely centered on himself. The person who spends himself on preaching the gospel to the point of being martyred is completely centered on Christ. The person who is very sick and in great pain and accepts such pain as his cross is centered on Christ as well. Centering our lives of Christ makes all the difference.