You’re time criminals. Not going on jaunts across the millennia - the Watchers have that tech locked down. But you can rewind and fast forward, branch and merge timelines. Whether you’re assassins, burglars, spies or vandals, the job is the same: split off a branch from the main timeline, understand it thoroughly, do what needs to be done and reintegrate the branch with the main timeline with a minimum of fuss. Simple, right?