Alma 36:11 - 36:15
Alma 36: 11 And the angel spake more things unto me, which were heard by my brethren, but I did not hear them; for when I heard the words—If thou wilt be destroyed of thyself, seek no more to destroy the church of God—I was struck with such great fear and amazement lest perhaps I should be destroyed, that I fell to the earth and I did hear no more.
Alma was in so stark amazement that when the angel spoke more to Alma, he did not hear him. When Alma heard the words that he would be destroyed if he and his fellows continued trying to destroy the church that he collapsed. He did not hear what else was to said to him or the others.
Alma 36: 12 But I was racked with eternal torment, for my soul was harrowed up to the greatest degree and racked with all my sins.
All the was on his mind was the chilling thought that he was a candidate for eternal torment. He could only think about the evil things he had done and the reward that was do him at this point in his life. He knew that it was not going to be a good outcome. His conscience was now pricked and he was aware that he had done very evil things and he was sorry for it.
Alma 36: 13 Yea, I did remember all my sins and iniquities, for which I was tormented with the pains of hell; yea, I saw that I had rebelled against my God, and that I had not kept his holy commandments.
In his comatose state he was remembering all his evil acts. He was hauled over the hot coals of a sheered conscience and he was feeling what it was like in hell for all the unrepented souls who end up there. He knew it all began at his rebellion against God and the commandments.
Alma 36: 14 Yea, and I had murdered many of his children, or rather led them away unto destruction; yea, and in fine so great had been my iniquities, that the very thought of coming into the presence of my God did rack my soul with inexpressible horror.
He was reminded of all those who he had caused to leave the church and follow his example of not living according to gospel principles. As he thought about that, he was in great fear of standing before God to account for this.
Alma 36: 15 Oh, thought I, that I could be banished and become extinct both soul and body, that I might not be brought to stand in the presence of my God, to be judged of my deeds.
His first thought was to try and figure out how he could get out of standing before God by maybe becoming extinct of just plain disappearing forever. The thought of standing before God was not a pleasant prospect.