Hermes was connected to church at Rome, or at least Tradition tells us this. In this, he would have no doubt had a long standing access to Peter’s letter. While this may not be an exact interpretation of 1 Peter 3.18-4.6, Hermes most diffidently has a certain strain of Tradition in mind which may help us understand how the early Church thought of the ‘preaching to the dead.’
“Why, sir,” I asked, “did the forty stones also ascend with them out of the pit, having already received the seal?”
“Because,” he said, “these apostles and teachers who preached the name of the Son of God, after falling asleep in the power and faith of the Son of God, preached it not only to those who were asleep, but themselves also gave them the seal of the preaching. Accordingly they descended with them into the water, and again ascended.|But these descended alive and rose up again alive; whereas they who had previously fallen asleep descended dead, but rose up again alive.¦ By these, then, were they quickened and made to know the name of the Son of God. For this reason also did they ascend with them, and were fitted along with them into the building of the tower, and, untouched by the chisel, were built in along with them. For they slept in righteousness and in great purity, but only they had not this seal. You have accordingly the explanation of these also.” (HSI 16:5-7 APE)
This is describing the Harrowing of Hell in which Christ (and by Hermes account, the Apostles) rescued from the hand of death those disobedient souls in prison.
Further, there is this notion from the 2nd century Gospel of Peter:
X. 38 opened and both of the young men entered in. When therefore those soldiers saw that, they waked up the centurion and the elders (for they also were there keeping 39 watch); and while they were yet telling them the things which they had seen, they saw again three men come out of the sepulchre, and two of them sustaining the other (lit. the 40 one), and a cross following, after them. And of the two they saw that their heads reached unto heaven, but of him that 41 was led by them that it overpassed the heavens. And they 42 heard a voice out of the heavens saying: Hast thou (or Thou hast) preached unto them that sleep And an answer was heard from the cross, saying: Yea.