Complex sentence: After he and Lori save Janet Cunningham, George realized that he was next on Death's list, and attempts to take his own life, but his failed attempts led the trio to believe that saving Janet ruined Death's plan.
Split into simpler sentences: After he and Lori saved Janet Cunningham, George realized that he was next on Death's list. George attempted to take his own life, but his failed attempts led the trio to believe that saving Janet had ruined Death's plan.