Curious Passage in Clement of Alexandria

We all know that 'Paul' wasn't the apostle's real name. Whatever it was, it was given to whoever the apostle was after he converted to Christianity. While the Acts of the Apostles says that 'Shaul' was who the Apostle was before he took on the name - or title - 'Paul' (it is never fully explained of course) shaul in Hebrew means 'grave' or by extension 'underworld.'

There happens to be a curious passage in Clement of Alexandria which refers to at some of the apostles preaching to the dead in the underworld. The passage reads:

it is evident that those, too, who were outside of the Law, having lived rightly, in consequence of the peculiar nature of the voice, (Sylburgius proposes to read φύσεως instead of φωνῆς here) though they are in Hades and in ward, (cf. 1 Pet. iii. 19) on hearing the voice of the Lord, whether that of His own person or that acting through His apostles, with all speed turned and believed. [Stromata 6:6]

I can't even imagine a scenario where Peter or Andrew descended into the underworld to preach to the dead. But someone identified as 'shaul' before he took on the name or title 'Paul' might fit into this tradition, no?