Board Thread:Episode Discussion/@comment-24573226-20170121144613/@comment-26397825-20170121170850

ChishioKunrin wrote:

I felt like it happened because he became determined to do something, like his father said. "Sometimes the worst thing you can do is nothing."
 * I'm in the "calming people/removal of negative emotions" camp, considering that his Semblance happened when he was having a panic attack that prevented him from taking action, and once it happened, he calmed down.

Ren gets determined to do something, his aura is unlocked and his sembalnce activates, he runs to do it (probably without even realising that he's protecting the two of them from being foun dby Grimm).