The two Jacks walked out of the Order of Magi's hut. They continued walking away and went into an alley. Inside the alley, they looked around to make sure that no one was following them. The Double Clone ran out of duration then. The two Jacks disappeared. Both of them were clones.
Half an hour ago, when Jack stepped into the portal into the obelisk plaza, he did several things while in transit. There was a one-second gap between the time he stepped into the portal and stepped out to the obelisk plaza.
During this one second, he cast multiple spells. He first used Dragon Eye to expressly cast his first spell, Superior Acceleration. Once accelerated, he cast Double Clone and then Invisibility on his real body.
When he came out of the portal, he quickly located Janus' position. While invisible, his real body used mana concealment and moved away from Janus.
