[In his surprise at finding another Souji present, Armin had somehow completely missed the hole in the sphere. He kicks himself internally for being unobservant.]

Oh, I see. [He almost asks if it was Naoto, but - barely - manages to stop himself before freaking Souji out even more at why a total stranger knows so much about him. Save that revelation for later.] Well, there's the pencil, you can draw your way out. But since there was already a hole - in liminal space, gravity can be in whatever direction you want it to be in. So you could actually have just walked to the hole - though you'd have had to be careful about falling through.

[Armin calmly walks halfway up the sphere to demonstrate, stopping when his orientation is perfectly perpendicular to Souji's - and there's no denying that gravity is not pulling them in the same direction.]