Really? That's rough. But it's not like Shcherbakova did not deserve her marks, so I'm not sure why she should have been so upset. Is there anything in the background going on?
I don't think there's bad blood between them otherwise - they are sharing a room in Beijing. And of course, while Shcherbakova is also overscored Trusova is the most overscored in PCS, so from that point of view she couldn't complain. I think it was all just too much. There must have been immense stress, imagine all the years of extremely hard work, they are practicing practically all day long, don't each much, are under constant stress and pressure to prove they are good enough to even get one of those three Russian spots at international championships. And who knows what else they had to put up with. The stories I have read in the past few days - well, I don't want to spread anymore rumours and I don't know what is true, but let's just say that Alena Kostornaia broke her second arm recently after just getting back on the ice. And it's not like it's normal for figure skaters to constantly break their bones.
Trusova strikes me as a generally nice kid, with emphasis on kid, because she seems very childlike for her age. And then all the stories and of course suspicions that they might be doped, too... that must all be very much.
Rationally she must have expected not to win gold in advance, Valieva was always the over favourite - now it was Shcherbakova instead, when maybe she had thought that at least they together were overtaken by Valieva, and she's the only one who doesn't get gold. (I don't think Valieva will keep her gold, but I think they told the girls it would stand, and they probably also put Trusova's hopes up at one point.) And I think in that moment, when she realized she had done her five quads, not perfectly, but all somehow landed, and Valieva failed, and it still wasn't enough...
I don't think there's much of a rational explanation or actual entitlement, just raw emotion from all the pressure and hopes and splattered dreams.
She should actually get some of the worst PCS in the women's field, but I feel for her. I don't think she thinks she'll get a second chance to go for Olympic gold.