Vanishing in plain sight was a fundamental skill, a shinobi-iri based on various aruki, or footwork. It might seem as if Satoshi was simply retracing his steps towards the safety of the inn, but in the cover of the night it was all too easy for him to disappear off wherever he wanted to be.
Thinking that Satoshi had gone back to where Toshin was, that left Kayo and Ikari with Sawada, now with Kayo having a more personal stake in the matter. Ikari was out of the city, otherwise he might have tapped into his network to find out more. As it were, they were now confronted with a decision: follow the trail straightaway, or wait till the next day for the higher authorities to arrive? Satoshi was aleady ready to go, for he needed to get to Itsuno for his own purposes.
OOC:
So, set off now to follow the trail? Go back and talk to the patrons in the inn to see if they know more things? Offer to help the night watchmen convey a message to the authorities? Or something else? All options can lead somewhere, just saying.
Redcroc, typically no roll needed to disappear, unless Satoshi is in a situation where he might be watched.
That said, for fun role-playing purposes, since Nebula says Kayo watched him vanish, we can take an opposed roll from each of you to see if she spots him. Satoshi would roll Swiftness, and Kayo rolls Spirit. I was going to give Redcroc a bonus for having a smokescreen skill, but that's cancelled out by Kayo's sixth sense skill. (Note I'm very open to interpreting your skills liberally to suit various situations).