K-DUR

This is a patient question with me as the patient. I was in the ER today for dehydration, found my K+ to be 3.3 so I was given 2 K-Dur. I can't swallow pills and the nurse said I could cut them in half and I started chewing them and downing a bunch of water. She was just laughing like it was no big deal. As I'm not familiar with potassium supps, I went online and read that you are never to crush or chew them! What's with this nurse?? I did notice mild vague chest pain a 1/2 hour or longer after taking them that way. I'm ok now, but how dangerous is what I did? I called the ER back, the nurse was like "Oh we've crushed them for patients before, it's fine.." I called a pharmacist and he said at worst it wouldn't be as effective as swallowed whole. From what i read, it actually would flood my system with too much K+ and be dangerous. Should I be worried? Geez...