They're kinda suspicious, but anyone would be suspicious about a bunch of new people showing up at once. For all we know, she told them we were from some other part of the tunnels. [He imagines most people wouldn't go that far out of the city considering what he's heard about the state of most of the tunnels. It seems potentially believable that a new group of people could have shown up from another area without them knowing until now.]

But if you're taking the cynical route, why even let us into the city in the first place? They have all the advantages, they could've bottlenecked us in a tunnel before we even got here if they felt like it.