I really can see Ardent offering himself to Pate if there is any indication given that this will stop the Monster's rampage and save lives. This will shock Gavia to the core who really, really didn't think that he had it in him.
That said, there is some doubt as to whether things go that way. Another possible outcome is that Alice swoops in to extract Sedna and then flees without engaging the Monster. As the cart pulls away and the town in the mine starts to burn, Gavia criticises her for pitilessly leaving the archeophiles to their fate. "I know what that thing is," Alice replies. "I know what it is capable of. I couldn't stop it; an army couldn't stop it. If we'd stayed, we'd just end up dead too. The minute it went onto full auto, they were all dead already; they just hadn't stopped twitching yet."