1.   All kinds of wild ideas ran riot in my brain.

2.   Ann let her imagination run riot as she wrote.

3.   Because of her weakened state her imagination had run riot.

4.   He uses painting as a way of letting his imagination run riot.

5.   He was running riot, switching off lights and knocking things over.

6.   Now, when far greater things were at stake, she had allowed her emotions to run riot.