[Immerito]

"can easily mean someone or something is between a person and an exit or way of escape." The word for this is "cornered". "pinned" means to "hold fast or prevent from moving". Therefore, there is the nuance that the thing pinned cannot move. Whereas a cornered thing is physically capable of moving, but recognizes that movement is inadvisable or unwise.

[brytlea]

It is so commonly used that you look like a fool to try to say otherwise. Google “soldiers pinned down by sniper”. And if you look in your thesaurus you will see that “pinned down” and cornered are synonyms. Amazing.

Look, you are so determined to figure out a way that you are not wrong that you are grasping at straws. You would be so much better off to stop now. Hardly anyone else is still reading this, no one will notice. Wait until more information comes out. Perhaps you are right and this was sweet little puppy and the officer was a blood thirsty killer simply out to kill kill kill! But you are really torturing the English language and that’s very very cruel.