Which believers were living in Sodom when it got burnt?
As your verse indicated, the Lord separates His people from those who aren't.
Judgment begins at the house of God.
Those who 'intended' to live ungodly in Sodom remained lost. They never were not lost, John 3:18.
Taking another example from Sodom: Lot's wife was saved from Sodom, but disciplined as being a pillar of salt.
The believers are the salt of the earth. But if we lose our saltiness, then we are disciplined. But all such discipline..............
is temporary.
To suggest, or worse: argue, that God can or would throw some of His regenerated children into the lake of fire for eternity,
shows that you might be one needing and receiving some discipline. If you are a believer.
Certainly it shows utter ignorance of a Father's love and purpose and life.