Dodging a light attack doesn't make you faster than light. After all the light attack comes from a certain distance and still needs to reach you. Meanwhile you only have to move your body away from it.
Well half you body is less than 25cm (if I don't take your arms into account)
So we're talking about moving 25cm or less + half the diameter of the beam. Which most likely wasn't that insanely big. Logically speaking depending on the distance you need to move to avoid the beam and the distance the beam needs to reach you, you could be a lot slower and still dodge it. Well there is also attacking time and reacting which also makes a big difference.