Arab leaders facing public revolt have increasingly concluded that it is better to shoot to kill, or at least to arrest and imprison, than to abdicate and flee. That calculation appears to be based on the short-term results of the Arab Spring. Those who have left, namely Hosni Mubarak of Egypt, face the humiliation of a criminal investigation, a trial and possible imprisonment. Those who have opted to stick with the use of force, like the president of Yemen, Ali Abdullah Saleh, have retained power and appear to have leverage to negotiate immunity should they leave, regional analysts said.