The Utterances of a Peculiar Mindset

Q: Light slows as it passes through water or glass, causing it to bend, but how can it return to light-speed on its own once it exits?

A: This is impossible in today's science. No object in nature can speed up of its own accord after being slowed. A bullet doesn't spontaneously speed up after it is slowed by passing through a wooden block, so how does a photon of light mysteriously return to its original speed once it exits a glass block? Also, continuously shining a light beam through a glass block will heat it, creating the further mystery that the beam actually loses energy as it passes through the glass, yet still manages to accelerate to its original speed upon exit. Today's science cannot explain this mysterious everyday occurrence.

Here is another related mystery:
Bounce a light-beam between two parallel mirrors at a slight angle so that the beam bounces along the mirrors in a zig-zag pattern. How many bounces will it take before the light beam loses energy and slows down appreciably? 1000 bounces? 10,000? Of course, we know that the light beam will never slow down no matter how many times it bounces back and forth, despite the well-established fact that light imparts a small momentum punch when it bounces off objects (the principle behind solar sails). So, how does a single beam of light impart countless momentum punches as it zig-zags between the mirrors, yet still manage to emerge afterward at the same unchanging speed of light? According to today's science this is an impossible energy-for-free event.

Any explanations???