What the Lord actually meant by saving one's psyche here should be evident from the preceding four points. Peter and the other disciples already had eternal life. They did not need to do anything else in order to get it or keep it. Metaphorical language is being employed here. It is a sort of riddle.
All believers have eternal life.
Suffering precedes glory in God's plan. It did for our Lord and it will for His followers as well. We must give to receive. We must lose to gain. By sharing in our Lord's sufferings.