Common sense and experiment both say that someone standing on the ground will see the faster throw coming from the roller coaster. Now repeat the experiment pointing a flashlight straight ahead and measuring the speed of its light. Oddly enough, it won't matter whether you're sitting on a roller coaster, a space ship, or your front porch. The speed of light is constant, immutable. And it doesn't matter where you observe it from either.
Light speed is light speed.
End of story. Very counterintuitive, as physicists like to say when explaining stuff that obliterates common sense. After all, it was a similar test of the speed of light, the famous Michelson-Morley experiment of 1887, that set the stage for the scientific revolution called relativity. A kiss is just a kiss. A theory starts as a mere explanation for how nature works.