This doubtlessly means: "Even if thou will not of thyself be destroyed."
When the angel departed, Alma was overcome and dismayed; soul stricken, he sank to the ground. When his companions gathered around him, they found he could not move, neither could he speak. Outwardly, he was dead to the world. The torments of the damned had taken hold of his soul, and, in the most bitter pain and mental anguish, he lay racked with the remembrance of all his past sins. The thought of standing before the Bar of God to be judged for his iniquities overwhelmed him with dread. He desired to become extinct, both body and spirit, so that he could not be brought before his Creator. Thus for three days and three nights he suffered the pains of hell. (See Alma 36:16. According to the author of the Book of Mosiah it was for a period of two days and two nights.) We prefer to accept the former as being correct because it is Alma's own statement. Whichever it may have been, in his racked conscience, it must have seemed an eternity.