They were approaching it now, the intersection Kimura had been unable to put out of his mind for the past month. Unlike Asakawa, who was haunted by his failure, Kimura was able to look back at the accident fairly objectively. After all, he hadn't been responsible for the accident, so he hadn't had to do any soul-searching because of it. It was entirely the other guy's fault, and no amount of caution on Kimura's part could have warded it off. He'd completely overcome the terror he had felt. A month... was that a long time? Asakawa was still in thrall to the terror he'd known two years ago.
"thrall"の単語が分からないので "in thrall to" が分かりません。"thrall"を辞書で見ます。
・Merriam-Webster's Online Dictionary: a state of servitude or submission: in thrall to his emotions
・Macmillan Dictionary: in thrall to: completely controlled or influenced by someone or something: He accused the government of being in thrall to big business.
・Vocabulary.com: When you're in thrall to someone, you are under their control in some way. If you're being held as a hostage, you're in thrall to your captor.
You can be in thrall to anything that holds you captive or controls your thoughts or actions, like an addiction, a disease, or a cult leader. The Old English word that thrall comes from literally means "slave" or "servant." Another word with the same root as thrall is enthrall, which is sort of a friendlier version of the same idea. If you're enthralled by someone, you're captivated or fascinated, rather than "held in bondage."
なるほど、"thrall"は元々奴隷/虜で、 "enthrall" だと良いニュアンスが出てくるのですね。