#3 –
I forget which episode it is but Andy and Sullivan are at the end of a shift and Andy brings him dinner. And they talk about "bright spots".
Andy looks at him surprised and says "eat your food"
Sullivan smirks and continues eating. They talk about life, and what brought them to firefighting, for Andy it was following her dads path, but since she'd grown up around the station it had quickly become her passion. Sullivan opens up about a fire at his house when he was young and how his young self were amazed at what the firefighters did, and how they handled things. It was a minor fire but they responded quickly and put it out. And after it was out, they talked to him about the trucks job etc.
They finish their food and an awkward moment passes, and Andy finally says, since we're friends now, why don't we go play tourist in our city, it's been a long time since I did that. Sullivan smirks and agrees. They end up spending the day together, and go their separate ways.
Later, Andy texts Sullivan to ask a question and he invites her over. She goes and they end up in bed.