14:10he also will drink of the wine of the wrath of God, which is mixed in full strength in the cup of His anger; and he will be tormented with fire and brimstone in the presence of the holy angels and in the presence of the Lamb.

This is a continuation of the previous verse.

he also will drink of the WINE of the WRATH OF GOD,

Today in this "mercy and grace" period, we cannot fully comprehend the "WRATH OF GOD". We wonder how a loving God can be this way. But God, first of all, is holy, and a holy and righteous God will not tolerate any other gods before Him (Exodus 20:1-3-17) including the beast and his marking system.

In verses 9-11, this WRATH is placed on each individual who CHOOSES the mark of the beast. However, countries also will come under the same WRATH (Jeremiah 25:15-29).

which is mixed in full strength in the cup of HIS ANGER;

This is not diluted (with water, implied). If one believes the relationship between water and spirits, then this says these individuals will not be able to get assistance from evil spirits to ease the torment. It is their CHOICE to take the mark, and thus they must suffer the FULL CONSEQUENCES.

Revelation is about "presence" as in chapter 4. Individual pride and arrogance don't stand a chance in the presence of purity. And since the angels and the Lamb are "forever" beings, this torment is forever. The strict separation of evil from good is monitored by the holy angels and by Christ himself (Matthew 25:46, Romans 2:3-11, and 2 Thessalonians 1:6-9).