Ch'lana looks very concerned.
"I assure you such things would never be part of any test I might give you. This is very troubling. The visions you describe - hallucinations might be more accurate - seemed to use things from your backgrounds and fears you hold. I do not think this would be any external threat. I would have sense any such manipulation of the Force, and I senses nothing until you both called upon the Force to free yourselves from the hallucination."
He turns to Nightshade. "Nightshade, I do not think there is anyone else on board, but it is possible my senses have been deceived. Would you please search the ship for evidence of anyone else? We have been in hyperspace now for a week - if someone else is here, they have been here since we left, and would leave signs.
"Collan and Niil, go to the cockpit and run a diagnostic on the main computer and internal sensors. If there is someone here, they must have tampered with both systems to avoid detection.
"For my part, I will meditate on this."
The three of you split up, Collan and Niil heading to the bridge while Nightshade begins a thorough search of the ship.
It takes a couple of hours, but by the end of it Nightshade has found no evidence of any other sentient being on this ship, and both the internal sensors and main computer check out. Nightshade joins Niil and Collan on the bridge, and you wait there together for perhaps a quarter of an hour before Ch'lana joins you.
"What have you found?" Each of you reports your findings, and Ch'lana's frown deepens. "It is as I feared then..."
Ch'lana takes a seat.
"I believe there are two things occurring here, as Collan had surmised, and I fear one of them is my fault. We will get to the second one in a moment.
"There is a bond that forms between student and teacher, and that is even more true when both are Force-sensitive. What one does can have an effect on the other. Normally the Jedi were concerned about students exposing masters to risk, and guarded against that. But I fear that I have placed the two of you at risk, and so all of us. I should have known better. Demaia tried to warn me, but I would not hear anything she had to say.
"I have..." He stops, and starts again after changing tacks. "In the past, I have had trouble following the Jedi code. At times, I have let my emotions rule my actions. This is highly dangerous, because doing so opens one up to the Dark Side of the Force. I carry such stains and, I fear, though our bond as student and teacher, I have exposed you to this. The Dark Side acts on you, through me. My past failures put you at risk."