When Rachel emerges from her room in her birthday skirt (which she got by exchanging Monica's gift to her) she removes a bottle of red wine from the refrigerator, turns and walks toward the kitchen table. She then places a bottle of white wine on the table and the red wine is now on the counter top next to the fridge.
When Rachel is leaving to go to the airport, after Chandler says "Deal with me first", she goes out the door. As the door is closing, she turns and goes to the left. The stairs are to the right. Going to the left leads nowhere except off the set.
However, there would be a stairway at that end of the hallway even if the usual practice is to go to the right. To say that way is "off the set" makes no sense in relation to the world the characters live in.
Rachel is shocked to find out about Ross' feelings for her. But at the very beginning, when she first arrives after running out on her wedding, Ross tells her that he had a crush on her in high school, and she said that she always knew.
However, TV shows are allowed to freely change back stories and events in future episodes. There were several things in the pilot episode that were subsequently changed.
When Rachel is about to leave for the airport and Phoebe is holding up the picture, you can see what appears to be set lights in the corner of the room near the ceiling.