Rereading that thing, and I have to explain obvious thing you can find in the internet, what scientist agree on.
Heat doesnt have enything to do with light speed. Emmitted light speed doesnt change, the way may be blocked tho. So photons can bounce, but they dont stop. They can be absorbed, they can be changed to something else.
Now about time. Light: nNothing gets FASTER. so nothing gets there in SHORTER time. If you have max speed, your time to arrival will be max short. At one end is the ULTIMATE and nothing past that, and on the other end is also ULTIMATE and nothing past that.
Time is motion and space, you cant separate them, its a relation. If speed increases, time it takes to reach destination shortens, see it as the very quick car, you will be faster at the target location. If you give it all the speed allowed in the universe, time it takes to arrive shortens to… nothing! And even when universe is expanding faster than light speed, it would still take zero time to reach destination, the wave is only stretched by space, nothing changes for it. It changes for you when you absorb it. If there is nothing that can absorb light, nothing to curve a light beam, then it still does max speed, and time it takes to reach destination is zero.
ATTENTION: THIS IS NOT SOMETHING INTUITIVE FOR HUMAN.
Photon speed is boundary that cant be broken, for photon everything is instant, it gets from point a to b in NO TIME at all, because its speed is the limit ANYTHING can move, There is nothing more past that.
Now something from me personally:
Everything already happened and we only are played like a tape in walkman.
The beam of light will travel exactly with light speed, and will reach exact destination with that speed, and nothing will be there faster. So you can assume It already did overtake your thought, your lifespan, every moment of your life.
This also means there is no time, only speed and location, and everything already reached the destination, same as you will reach it, just slower.
It is all predestined. Your birth was, your death is. You just dont know it yet, because you are too slow to see it (you have mass), but there will be location, where last light (for you) you will see with your own eyes.
It all have to reach the destination specified.