She watched the scissors in the mirror like the hand in the reflection wasn't hers, like it wasn't her who reached up, opened the blades with a too-easy flex of muscle and skin. She closed her eyes. If she couldn't see it, then it wasn't happening. Snap. When she opened her eyes again, it wasn't as bad as she had thought. Wisps of newly dyed blonde hair sank to the carpeted hotel floor. Her face looked uneven without it attached to her head, but then it didn't look quite right anyway, being the wrong colour. She raised the scissors to the other side of her head, and didn't shut her eyes this time. Snap. No, it really wasn't that bad, she thought as another clump of hair settled by her feet like a corpse at a crime scene. There, she thought, meeting her reflection's eyes, much better. She chopped off the rest, and then trimmed the ends until what was left of her hair was neat and straight. She brushed the stray strands off her shoulders and stepped back away from the graveyard of hair in front of the mirror.
Her family had taken her to England once, when she was little. She didn't remember that much – she must have been about nine or ten – but one odd thing she did remember was walking back to the B&B through a churchyard, running ahead of her parents and being told to stop and wait. It was then that she looked at the gravestones around her, and the engraving on one of them struck her nine-or-ten-year-old self cold, for on that one little grave, the date of death was the same as the date of birth, and this was a thing that young Ada had never come across before, a thing that she found it difficult to comprehend. When her parents caught up to her, she walked quietly behind them, her mind stuck on the name on that gravestone.
She considered it now, years later, as she scraped the hairs off the carpet, the last remnants of Ada Riley-Austin, and put them in the trash. Bin, she corrected herself mentally. They say "bin" here and so must I. She mused upon what a strange word that was as she sat down on the bed. She remembered once, in maybe about sixth grade, convincing a girl she'd never met before but was forced to sit next to in class that she was English, and it was only when she'd continued to say pants rather than trousers that the girl (who, it turned out, had English relatives) noticed that this was not the truth. The stakes were higher this time, much, much higher, but Ada knew she'd manage it; she didn't make such childish mistakes anymore.
No, that was not the part that scared her, the bit she feared she'd slip up on. She'd had different names before, different facades, but underneath it all, she'd still been her, she'd still been Ada Genevieve Riley-Austin, the only daughter of a firefighter and a drama teacher. But not this time. Not anymore. Ada was gone with the hair she'd chopped off, everything she'd ever been gone with a few snips of the scissors, and although she still looked very similar to how she'd always looked, the reflection that stared back at her now was the reflection of a stranger.
England was the one place she had ever been outside of the United States, the only place that she felt could possibly offer her something akin to comfort and familiarity. She may have been trained to deal with dangerous situations, to survive through chaos and pain and death, but this time was different. She thought it might make it just that little bit easier, to be somewhere she'd been before, even if it was only once, twenty or fifteen years ago.
She stood in front of the mirror one last time before she went to bed, her application for her new passport – her British passport – in her hand. Tomorrow, she would get her picture taken for it, tomorrow she sent it off, because that was all that was left to do now. She would burn the old documents, the passport and the used one-way flight ticket, the ones with her old name on them. She looked her reflection dead in the eye and tried her new name on her tongue, tried to attach it to that reflection, to her image of herself. Mary Morstan, she thought. Mary Morstan. But no matter how many times she thought she succeeded, still her mind gave her images of that little gravestone from all those years ago.
Mary turned out the light and pulled the covers over herself. Ada had blown her one chance at life now, and there was nowhere for her to escape. But the girl who never lived to see a single whole day she would get her second chance. And Ada would make sure that Mary Morstan never blew that chance.
Disclaimer: Mary Morstan does not belong to me, she belongs to (presumably) Mark Gatiss and Steven Moffat, although technically she originally belonged to Arthur Conan Doyle. But my point is that she's not mine, so there.