I don't understand it either. At first I was really happy because that is the crown that Morgana is wearing!
Now I'm just confused about why Gwen is anywhere near the crown?
Unless she really is begging Arthur not to crown Morgana (die, evil Gwen whorebag who kisses everyone in sight, die!
Oops! Sorry, my evil side got loose again ). Or... maybe she's being sentenced for saying something against Morgana? One can hope!