Lance is a lot sometimes, it's true. But he knows when to lean back and give someone space to get their thoughts and words together. So he waits as Midoriya thinks through and doesn't push at all. If he doesn't want to answer, Lance assumes that he'll just hold back.

When he does explain, Lance listens and takes a minute to think through the heaviness of what he's talking about. He nods slowly, "I only went there twice since I was kinda busy, uh… fixing up Prufrock." And he was massively injured, still, "But twice was enough… you're worried about when November rolls around again?"

Lance had assumed something sooner by 'that time coming up' and technically the Zealots aren't gone, just far less active. But if that's what Midoriya means… he can't say he blames him for that anxiety at all. If he knew the sinkhole was a seasonal occurrence, it would've had him tense his entire time in Deerington.