While it's unlikely we'll attain some sort of directly stated reason, one that could be inferred would be: his incredibly mastery of the Force and the powers it can provide.
Throughout the film we've seen him wielding immense control of his ability to use the Force, from delving into the minds of others to even stopping a blaster bolt in midair, which we'd never seen on film before.
One ability that has been shown is the ability to run away quickly by using the Force, known as Force Speed. Qui Gon Jinn and Obi-wan used this ability early in Episode I to escape from Droidekas that were attacking them.
As such, it's possible to assume it was Kylo's sheer mastery of the Force that allowed him to get ahead of them so quickly.