it was just stupid, clumsy and utterly lacking in subtly like everything the showrunners do. they had to behead her friend like the day previous (for absolutely no reason), because otherwise how would viewers know she was all emotional-like. and then they spent a total of like three minutes on her devolution into kinda-sorta burn-them-all targaryen madness. and then they had to make her choice so obvious as to slap the viewer in the face. like they could have started her off flaming up a bunch on non-surrendering soldiers and then she could just keep going in the firelust of a targaryen at war. or they could have had her fly off to flame at cersei despite the surrender and then things could get out of hand or whatever. but, because they're rough ridin' hacks, they just have her sit her dragon down for a spell and then with no provocation or motive whatsoever, start off on the nearest women and children. they're just so bad at writing.