They've slowed light down to a crawl before by passing it through chrolo-something and the guy walked faster than the light right next to him.
I just wish I could find the video.
Only because a Danish
(female) scientist proved it could be done by reducing it to like 60 km/h first.
Sorry, but the credit should go to her, as anyone can solve the Gordian Knot and the Columbus Egg once someone has shown the way.
I'm still waiting for the huge effects on all science that were a major concern when she did (as a "constant" which a lot of other stuff is based on was suddenly not all that constant anymore).
Some of the early LASERs (Acronyms should be in all capital) used xenon flashes for stimulation, perhaps it's a clumsy (error laden) description of that, leading to the very strange LASER stretching wording?