This was very good sense but, at the moment, Jill hated Eustace for saying it. He was fond of being dreadfully matter.of.fact when other people got excited.
When Tirian realized that the two strangers could not get home (unless Aslan suddenly whisked them away), he next wanted them to go across the Southern Mountains into Archenland where they might possibly be safe. But they didn‘t know their way and there was no one to send with them. Also, as Poggin said, once the Calormenes had Narnia they would certainly take Archenland in the next week or so: the Tisroc had always wanted to have these Northern countries for his own. In the end Eustace and Jill begged so hard that Tirian said they could come with him and take their chance.or, as he much more sensibly called it, “the adventure that Aslan would send them”.