I have read section 6.7 of LOL a few times now, and I still can't wrap my mind around the following.
Bindings that were previously closed to outside code are now wide open for us to tinker with, even if those bindings were compiled to something efficient and have long since had their accessor symbols forgotten.
If bound symbols are essentially compiled down to pointers in the environment of the closure, how can you pass a symbol to the already compiled function, and the function somehow is able to compare the symbol?
I've been messing with the pantest example in clisp, and I can see that I'm able to change both acc and this inside pantest. I can compile and disassemble pantest, but all the symbols show up in the environment. If I had a lisp that compiled down to assembly, I might gain some more intuition, but the code is complicated enough that it will probably be too difficult to follow without explanation.
(I will come back later and fill in some more information here later)
In short (and slightly oversimplified), the pandoric-let macro has added in some extra code to handle the case of trying to get or set each of the different variables it introduces. This extra code remembers the symbols of the variables after the code has been compiled, but since it's the only code which needs that information everything else gets compiled down to very efficient pointer operations.
The functions which generate this extra code are pandoriclet-get and pandoriclet-set, both of which are tricky to read because they return code which depends on the symbols sym and val which are provided in the pandoriclet macro itself.