"You know, I don't think anyone has." Senku admitted, looking like he was considering that.

"I'm not sure what would happen if we tried to record the void..."

He sounded like he was intrigued. "I wonder how we could attach it securely. See-" He gestured at the train wall. "We don't have ways of damaging or modifying the train for some reason, so I can't imagine what it would take, so we can't just drill in a harness or something."