Laine rarely did pointless things, so there must have been a reason why he ran from the Chaos World to the doorstep of neighboring Hemenu, circled around, and then sent his humanity back.
Just as the doomed Pallas could not be born under the unilateral shroud of the power of Chaos, Laine could not possibly divide his own humanity within the world, which would have been nothing more than self-deception. Of course, he could do so in the Spirit Realm—but the very idea of a mortal flying out from the Spirit Realm was hardly reasonable.
That being said, although Laine had split his divinity and humanity, he was, in fact, quite aware of himself. The division might not have been as complete as imagined, with the most evident example being that the Chaos World itself could still detect the connection between the two, as well as his currently intact memory.
