As far as Andrew knows, Aziraphale's just some human with a funny name, but the evidence is in his favor so far as humanity not having already fallen to an outbreak of cordyceps goes. He sniffs in a deep breath, matching Aziraphale's look with one of deadly seriousness.

"You know who sent me," he says, because if Aziraphale didn't at least have his suspicions he wouldn't be acting this way. "I'm not going to tell them where I found you, not if they're set to experiment on her, but I'm not going to leave her here if I don't think it's everyone's best option."