.. How do I get out of this chamber before the culprit?

After you cross the ledges, the door at the end leads to what looks like the large room in the middle of tunnel 3, the one with the odd uneven floor. You're at the lower left, and the culprit is at the upper right, and you need to reach the door at the top center before he reaches the exit at the bottom right. Read to the end of this hint for a picture showing exactly how to do this.

If you count the steps the culprit has to cross, you can see that you have 13 moves to get out. But there's no time limit on this, so you can sit and plan out your path calmly until you're ready to move. All the same, you might want to save your game before you start.

To start, turn the colored stone once clockwise so the blue bar is pointing down. When you do this, Nancy says, "The stones come up from the floor when the colors match!" and many more stones appear.

As Nancy said, when any two stones have the same color bar facing each other, a path extends between them. After you make the first move, look at the next stone to the right. The stone you're on has a yellow bar facing right; turn the next stone so its yellow bar faces left.

You can turn each stone either clockwise or counterclockwise; since each turn is a step for the culprit, stop and think which way you want to turn a stone before you turn it.

You won't need to turn every stone along the way, since some may already be turned the right way. Do keep in mind that you need to create a continuous path before Nancy will escape.

You might find it easier to mentally solve this one from back to front. That is, see which stone is closest to the exit, then plan which stones connect to that stone, and so on.

Any path that gets you out before the culprit is the right one, but here's how I did it: