Well it is, and now you know! [Maybe Hange could have mentioned such an important fact at an earlier time, but hadn't because they did not envision a time when either of them would be alone with no contact for an entire week. They left Levi in the city, sure, but he did have other people around to fulfill that need.]

[Or maybe Hange also didn't mention it because they did not want to tread too close to a conversation about how they had been researching it because they were absolutely thinking about testing it out on purpose, before backtracking on it after the whole 'promising not to die' pact the two of them made, it would have been in poor taste.]

Talk to who? I asked Gabi and Historia, Eren asked Jean and Mikasa if they'd seen you and they hadn't.

[Can you fault them for assuming he was alone if not with any of those six? It's not as though he regularly has other people over at the apartment to hang out. Hell, Levi and Eren barely hang out and they live together...]

[And while it is true that normally Hange wouldn't sweat it over something so trivial, because they have enough faith in Levi's skills, this is hardly a 'normal' situation when in a foreign world, and recovering from injuries.]

Well that's what happens when you leave me with nothing! I had nothing better to do than overthink it! And just so you know, Eren can be even more pessimistic than you when he wants to be.

[He was worried about you too, Levi.]