A Bottleful of Illusion

Connect to illusion, enter the Cave of Elements, fill the bottle with water and bring it to Charles de Doucer in the Refuge.

That's just incredible! You know what the sensors displayed? Nothing! Nothing at all! Once the machine started, your body vanished without a trace. It only came back now that we've returned from the Planar Rim. As for me, only my mind went to the world of illusion, while you were carried away entirely. Do you realize what that can mean?
But no, let's make no hasty conclusions. Now that the idea with the sensors failed, let's carry out a full-fledged scientific experiment. Take this bottle. It's an ordinary lab container that's absolutely empty. Try entering the world of illusion with it. For the time being, the Planar Rim leads only to the Cave of Elements. That's where you should go. Fill the bottle with spring water and get back here. Let's see the extent to which you can violate the border of the worlds.

I always thought I knew reality from fantasy well enough. However, if this experiment is successful, it will mean I knew nothing whatsoever all this time.

Unbelievable. That's water. Clear spring water! Your faith is so strong that you completely immerse into illusory reality. You can even bring quite real items back from there. This is imaginary water, it doesn't exist, but it's here - as if created out of nothing. I don't know what to say. This ruins all I ever knew about reality and illusions... However, that's an unparalleled advantage for the Resistance. This power is our chance to survive and stop Tep.