Tyki is correct to assume she'd freak out at an arm through her chest, and opting for a different demonstration turns out to be a good call.

The trick he shows her instead takes Rita by surprise despite the warning, and she gasps audibly when he suddenly sinks into the ground. Surely he knows what he's doing, and he chose to show her this way because he knows it's perfectly safe. But it's hard not to imagine a worst-case scenario... his body becoming trapped underground, or just sinking forever...

But that won't happen, right? Rita turns her head to look around, eyes on the ground. He'll surely resurface somewhere nearby, won't he?