That is not the worst case scenario. Notice the timelock that allows key B and key C to spend the money after 89 days. Very possibly, key A expected that he could use key D or key E to take his money back before the timelock expired, such that the timelocked path was only a less secure fallback that should only apply if he loses his keys. But due to bip110, neither party can spend the money until after the timelock expires, meaning the less secure path and the intended path will both become valid again at the same time. That creates an i race condition that is entirely bip110's fault.