Keeping mind the fact that Lord Zash was reluctant to confront Darth Skotia and Darth Nox sabotaged his cybernetics in order to defeat him, I'd say that Asajj Ventress is out of out breath here.
Skotia was a pretty insignificant Darth in the grand scheme of things. He was powerful enough that Zash or Apprentice Nox couldn't take him down without external aid, but those 2 would be humiliated by Ventress as well. The guards are essentially non factors.
Ventress.
__________________ ”You presume limits to my power. There are none.”
A very weakened Khem Val, that is. And the Terentatek was with Khem's assitance. And both were on DS nexuses, whereas Skotia would've also benefited from Dromund Kaas, so the nexus gets equalized there.
Khem Val might be weakened during this time but he remained a formidable threat and killed all acolytes who were unfortunate enough to meet him. The Overseer deliberately dispatched Sith Inquisitor to confront Khem Val, expecting his demise during this trial.
I am not sure if the acolyte would be permitted to have allies while completing his trials. Taking Khem Val along is a matter of personal choice.
They fought the Terentatek immediately after, with Khem being necessary to punch through that wall. And nobody knew about Kallig having Khem, so I don't know what "allowance" was required.
And I couldn't care less what a bunch of shitty acolytes couldn't accomplish on a nexus. Ventress contends with some of the best duelists in the mythos.