Scripture does not say refusal of the mark leads to death. You are confusing two different things:
Rev 13:15 And he had power to give life unto the image of the beast, that the image of the beast should both speak, and cause that as many as would not worship the image of the beast should be killed.
Refusing to worship the image of the beast is a death penalty.
Rev 13:16 And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads:
Rev 13:17 And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.
Refusing the mark isn't a death penalty. The only penalty is not being able to buy and sell which means no participation in the official economy. That would make life very hard but isn't something you will be killed for.
Here are people who refused the mark and survived:
1Th 4:15 For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.
1Th 4:16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
1Th 4:17 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
Some Christians will survive and be changed and raptured after the Great Tribulation has ended, at the second coming. People who have taken the mark do not qualify to be raptured. Instead, the marked will suffer the wrath of God in the 7 vials.