NKJ Revelation 14:10 "he himself shall also drink of the wine of the wrath of God, which is poured out full strength into the cup of His indignation. He shall be tormented with fire and brimstone in the presence of the holy angels and in the presence of the Lamb.
Notice that the texts says "Lamb." This idea will be particularly tormenting for those in hell who heard the gospel. They are not merely tormented in the presence of "Christ," or in the presence of the "Son of God." They are said to be punished in the presence of the "Lamb." Why is that so tormenting? Forever in their minds will be the truth that the Lamb was their appointed rememdy in this world. The Lamb was slain as their substitute and suffered that they might be saved. Rather than applying his blood to themselves through faith, they spurned the sufficient Saviour, and receive heightened condemnation as a result. They might have been healed by looking to the slain Lamb while in this world, but now hell is heated hotter by the vision and perpetual contemplation of Him and His office. The same Lamb that is the everlasting delight of the eternally redeemed is the source of torment for the eternally damned. Of all things, they are tormented by a "Lamb."