Gregorius will head down to the regio entrance the next morning, with Alcimus, Fray and any shield grog Fray wants to bring (if asked, Gregorius will suggest Aison (https://forum.atlas-games.com/t/covenfolk-character-sheets/5242/1), who Gregorius sometimes uses himself in situations where a monstrous wolf would be inappropriate).
He'll look for the regio boundary, and try to assess the conditions on the other side (and briefly report them to Fray). Then he'll suggest:
"I propose that Alcimus and I go through first, and then return immediately for you assuming we're able to. If we're not able to" he smiles "you may wish to consider yourself lucky. Viola also has Second Sight, as do at least one of those cats, so there should be other people able to relocate the regio boundary if necessary. I'll take an arcane connection from this side, but I have no idea whether spells to it will work across the regio boundary, and unfortunately I never learnt an arcane connection range communication spell. Still, better to have it than not."
He'll chip a small piece off one of his stones, keep it and leave the stone in the corridor.