the girl who fell the stairs was wearing a necklace as well as there is a chance that she might be wearing a wig…
it also could be ro-na because what if it wasnt a wig? you can see that the person who fell down the stair has the hair same a ro-na but idk. it also couldnt be ro-na because her mom was there when she fell down the stair and she would have scream or cried. but thats just my prediction.