I'm a going fishin'

Here's one of those work situations I never know exactly how to handle:

You walk into the shared kitchen, which is empty, and am assaulted by the smell of someone's fishy lunch. You can't tell if it's sitting in the microwave waiting to be picked up, or if someone has come and gone, leaving just the perfume behind. You get your coffee and, because you're a good Seattlite, fill your water bottle, thinking how no one should ever bring/reheat fish at work. Then you turn to go, and you pass someone coming into the room.

Do you:

1. nod and smile and walk on, leaving them to think the same thoughts about the fish, but associated forever with you?
2. say "get ready, someone reheated fish for lunch, and pee-yew!" preparing them whilst simultaneously letting them know that you wasn't responsible, and risking offending them because in fact it was their fish and their lunch?
3. scuttle away without making eye contact to write a quick blog post?