Revelation is a vision. The use of the words "kill" and "dead" are understood by looking at the context.
For instance, in Revelation 9 it shows that "killed" in context is equated with repentance and turning around from bad conduct: "But the rest of the people who were not killed by these plagues did not repent of the works of their hands; they did not stop worshipping the demons and the idols of gold and silver and copper and stone and wood, which can neither see nor hear nor walk. And they did not repent of their murders nor of their spiritistic practices nor of their sexual immorality nor of their thefts."
The plagues of Revelation are figurative descriptions of the attack on all religious institutions. When people see that the religious leaders are a bunch of fakers, when their refuge of lies is exposed by the "hail" of truth, when the angels stop holding back the winds of destruction and the nations come like locusts and take away all the financial stuff and real estate and holdings etc, then many religious people will repent from putting trust in religious hypocrites. They will be "killed" figuratively as to their former conduct. Some will look to God instead of their hypocritical Pharisaical leaders, since those leaders will be gone.
Jesus also showed this in his illustration regarding the scribes and Pharisees that hasn't taken place yet but will shortly...
"The harvest is a conclusion of a system of things, and the reapers are angels. Therefore, just as the weeds are collected and burned with fire, so it will be in the conclusion of the system of things. The Son of man will send his angels, and they will collect out from his Kingdom all things that cause stumbling and people who practice lawlessness, and they will pitch them into the fiery furnace. There is where their weeping and the gnashing of their teeth will be."
The illustration is figurative, another angle on the time during the great tribulation when religious institutions are destroyed. That the people in the illustration are not literally killed at that point is shown in that they are still able to "weep" and "gnash their teeth". The "fiery furnace" is figurative, representing the destruction of the religious institutions that formerly lent power and prominence and money to those hypocritical religious fakers.