The day before the expedition.
By now Christos is back from the Telchine territory. He made all the preparations that he could. He staked everything on the point that Sam might be related to the Hub. He is now praying to Zeus hoping that he can prove his speculations with this.
In fact, he would have liked to stay back at the Telchine territory waiting for Sam's twelfth labor, so that he could deal with him by himself.
However, he was informed by Bloody Chariot about the expedition, which made him unable to refuse.
And Sam is not showing any signs of going on his twelfth labor any time soon. Since he is way ahead of the schedule in completing the first eleven, the Poseidon academy didn't really have any grounds to pressure him.
Even if they do, they are not really bothered to it.