The time taken to draw up a peace treaty was relatively quick, the two sides having completed it within one day.
And even as it was being signed and the prisoners exchanged, Alexander could already see from atop his walls how the walls of the Tibian camp were being dismantled and soldiers being arranged in marching formation.
It seemed that Perseus was ready to march the second the deal was completed and he got his men.
'It is too bad we cannot finish them off,' And seeing so Alexander could not help but lampoon a bit at this lost opportunity.
No one was under any kind of illusion that the peace treaty they signed was a flimsy, tenuous one and that the attacks would resume the second it expired.
So if Alexander had the ability, he would have certainly tried to cut off the snake's head then and there.
And perhaps Perseus had sensed this, thus prudently deciding to make his retreat while he still could.