Your interpretation is in err.
For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit: By which also he went and preached unto the spirits in prison; Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.
1Peter 3:18-20 KJV
These spirits are related to the time of Noah (see Jude 1:6, 2 Peter 2:4) and not people who have passed away waiting resurrection or judgement.
You are mistaken, probably influenced by Peter's own mistaken interpretations.
Revelations 13:8 reveals that
"the Lamb was slain from the creation of the world".
Meaning, the creation of this world is what slays Christ. That is, the death and destruction of Christ (the "lamb of God") is prehistoric (before time begins).
2000 years ago, Jesus re-enacted, in persona, the beginning and the ending of the world of time. The cross/crucifixion/destruction/killing was a parody (parable in actions) of what the creation of this world (hell) does to Christ.
The "three days" he spent "dead", underground (so to speak), represents all of time from beginning to end.
The resurrection represents the end of time, and with it, the end of this world.
In time, that is, during the time of the "dead Christ", Jesus claimed his mission was "to tell the prisoners of sin that they are free". This is a reference to all mankind, which are like spirits kept captive in fleshly prisons.
Since the "death" of Christ was prehistoric (before time began), "he descended into hell" (per the apostles creed) means that the creation of this world (a world of time) is a descent into hell, this world being hell.
Here, in hell, is where he preached to set the "prisoners" free, by means of "the truth".
Hell includes all parallel universes, as well psychic regions of rest between incarnations. This will all come to an end with the "resurrection", which is the end of time.
Jesus, in identifying himself with the slain Christ, sought to teach us something about the beginning and the ending of the world, and how to escape ("overcome") the place of a "dead Christ". As such, this world, and all of time, represent the "tomb" of a "dead Christ".
If you are part of the experience called "mankind", you are a "dead Christ" due to your "unbelief" in who and what Christ really is. You are "here" because you are more loyal to your faith in all things that are
not Christ, than what actually
is Christ.
Your loyalty (to all that is not Christ) is revealed by the fact that you are satisfied and content (if not happy) that Christ die for "you" and your "sins". This means you are satisfied with the status quo, which is built by first rejecting Christ, as any kind of cornerstone.
Anyone abiding in this world, a world of time, is complicit in the pre-historic rejection of Christ, and contributes to Christ's "death" through faith invested against Christ ("sin").
Your faith is still invested against Christ, and needs a 180 degree turn to be effective toward salvation.
With this new world-view, you can understand baptism a little better, and why Peter compared it to the flood of Noah. Out of the flood, eight people survived, out of a whole world they had preached to, warning of disaster. The eight people represent the salvation of Christ, which is saving the "good" out of all the bad ("sinners"). Salvation is not for sinners. It is for Christ, the One-Only-Good. This is symbolized, by Jesus own baptism, yet another parody (parable in action). Left standing was "my beloved Son" (Christ, the Good).
The water of baptism is likened to the truth. If one washes one's mind with truth, such as i've presented here, one can be "saved" from the masses that are perishing daily, by getting into the boat of Christ, so-to-speak. Washing your mind with truth will help you
identify with Christ (get into Christ's boat, so-to-speak). The masses that are not saved, represent all mankind. The eight that are saved represent Christ. The water represents the truth, and the flood represents the fact that the truth will flood over all the earth. When it does, the world will come to an end. At the end of the world, only Christ will be standing, revealed by the removal of deception. Truth washes away the sins of the world, and with them, the entire world built with them.
Remember this: flesh is like dirt on the mind of Christ. Baptism is about truth for your mind, that you may reclaim the "mind of Christ". Once truth has restored health to the mind, all flesh will disappear back to the "dust" (nothingness, void) from which it came.
