I can’t find the Greek text, and I really don’t want to spend any more time on it, but this is what we hear Irenaeus say:
“And after their [Peter’s and Paul’s] departure, Mark, the disciple and interpreter of Peter, himself also handed down to us in writing the things preached by Peter”
Several scholars suggest that the word here translated as departure, ἔξοδος, simple means that Peter and Paul left Rome, only to return later and die. By rights, they may be correct to some extent, unless we can supply a better lexicographical meeting. There is a canonical source which does provide us with some suggestion that Irenaeus meant death, and further, that this word is in fact a very Christian understanding of death.
I mean, sure, there is Luke 9.31,
οἳ ὀφθέντες ἐν δόξῃ ἔλεγον τὴν ἔξοδον αὐτοῦ, ἣν ἤμελλεν πληροῦν ἐν Ἰερουσαλήμ.
But, that doesn’t really go well. Luke-Acts is connected to Exodus, and the use of the word here is only a hallmark of the author’s internal theology. We need something else… Something which connects Peter to this particular word and concept.
σπουδάσω δὲ καὶ ἑκάστοτε ἔχειν ὑμᾶς μετὰ τὴν ἐμὴν ἔξοδον τὴν τούτων μνήμην ποιεῖσθαι. (2Pe 1:15 BGT)
If you follow Bauckham, and to some extent Witherington, then 2nd Peter can be dated between 90 and 100 CE. If you follow some scholars, we can date it to 160. Origen has issues with it, but there is some hints at it in earlier (than 160) works. But, what comes first? If you are going to make a letter look authentic, you need to borrow from existing phrases. That argument is not to be balanced here.
On the other hand, regardless of the date, we can assume that one author is in the other author’s audience. 2 Peter used the word to signify death, or rather, the Christian notion of departing this world for the next.
Get my book sometime early next year. Boom. This is important.