The abstract of the paper says that the two fastest stars are traveling at 700 km/s. For scale, at that speed, a star would take 20 million years to travel from

The abstract of the paper says that the two fastest stars are traveling at 700 km/s. For scale, at that speed, a star would take 20 million years to travel from the outer edges of the galaxy to the center. (That ignores any acceleration as the star falls inward, of course.)