Out for leaving base during timeout?

[umpjim]

I'm baseball only. Read this about an NCAA game:

Freshman cleanup hitter Morales then whapped a stand-up double to the left field wall, scoring Nash to even the score, but Morales made a costly mistake by walking off the bag during a timeout.

“When the defense calls timeout, then the runners have to stay at their bases,” Libby said of the rule.

“The runners can come talk to me if their coach calls timeout to talk to their team. Then I’m allowed to talk to my team.

When it’s their players, you can’t leave the base.”

Perused the NCAA rule book online and it looks like there is a clause that you can't leave base for any reson. Is that what the out is called for?