Esdras was fine with that, it's not good to be too greedy besides he could figure something out until then.
As for his breakthrough to the first threshold, it would take months for him to complete that jump even with Tara's 'help'.
The amount of negative energy needed was massive and Tara wasn't providing as much negative energy as before. No matter how much he humiliated her it no longer worked, he even started getting a creepy feeling from her lately…
If he didn't need her for other things he would have disposed of her long ago.
Anyway, she will prove just how useful she was soon, during the Rite of passage in a few days time.
At first he thought of the Rite as something silly that he should get it over with but his need for negative energy could be solved very conveniently.
Heheh
There are many ways to expedite the process, why should he have to wait several months if he didn't have to? He was a modern man after all, he had to think of practical solutions.