In regards to the "pop into"/"run through" distinction, I was talking to a friendly Turkish man who was trying to learn English, and he said something that made me think. Namely, our prepositions don't often make that much sense. Consider - you can chill out, ease up, cool down, and pull back. They can all mean the same thing. Wow, the game hasn't even started, and I'm already talking about cats and grammar...