Follow them?

You follow Cersei and Jaime down the hall, being careful to stay just out of sight. This hall is empty and it eventually leads to a winding staircase. You can hear them whispering and moving up the stairs. When you are sure it is safe, you follow slowly. The stairs lead to an upper hall, that appears unused. Peeking around the archway at the top of the stairs, you catch sight again of the Queen and her brother.

Jaime has Cersei pressed back against the wall and is leaning in kissing her neck! His hands grope under her dress.