Sam stayed in the valley for one week. The ghost chimera also didn't budge for this one week.
He increased the torture levels, used his own mental energy to poke the chimera a bit, and destroyed the undead creatures that are connected to the specter one by one, making its mental energy weaker.
Sam knew better than anyone that he should follow through with this torture. By this point, the specter would be willing to die and if he killed it, then it would be more like a blessing than a punishment. So, he made sure that he brought the specter to the edge of nullifying its existence and then brought it back, never granting that relief.
In this one week, there is something else he has done.
Since he diverted all the torture from the formation to the Dormant soul. It has become weaker than ever.