Nobody, especially not her keepers, would ever know quite how she did it.
Much like the speculation that made the British media explode when her famous brother, a mere one year senior, returned from the dead some two years after his very public suicide, nobody would ever quite figure it out. They may come dangerously close… but not quite.
And Eurus Holmes was content with that.
She would go "on the lam" as the saying went, have her fun for a day, and be back in her containment cell by bedtime.
Sometimes she would wander around a random area of London, observing the homeless, the middle class, the ordinary civilization that made up the majority of humanity.
Sometimes she would pose as a volunteer in a daycare, interacting with children to see if she could possibly find the child she once was - the proper credentials were laughably easy for her to obtain to that end. Other times she would attend a symphony concert – never perfectly performed of course, but she had learned that lower expectations meant less disappointment and hence, more satisfaction overall. Perhaps Sherlock's interpretation of the pieces they played together weren't so flawed after all.
Sometimes she would attend a cinema matinee. She learned she loved popcorn – light on the salt, heavy on the butter, and cheesy picture shows. Not surprisingly, she found she hadn't much use for "chick flicks" although they were fascinating and enlightening for her – but mystery and suspense held her undivided attention, and the more far-fetched, the better.
Her absences became easier over time as her guards had become complacent and didn't notice.
The new governor was too occupied with other "uncontainables" at Sherrinford. Eurus Holmes had become so docile that she was now a part of the background of their assigned charges.
It really was too easy to escape once a week… and even easier to find her way back in, undetected. No harm, no foul.
Eurus was having the time of her life, and she had Sherlock to thank for awakening the humanity that allowed for that.
Of course it had taken time - years in fact. It took her a disappointing amount of time to deduce where her brother lived with his wife, Dr. Molly Hooper, and infant son Will, Sherlock's best friend Dr. John Watson, his toddler daughter Rosie, and their landlady, Mrs. Hudson.
Considering how popular they were to Londoners, she considered that maybe being clever wasn't always as important as being AWARE.
She didn't seek freedom to cause trouble, or torment. She sought it to find what made her fellow humans tick. What made them sad. What made them angry. What made them laugh. What made them cry. But most of all, what made them and content. Truly, uncontainably, content.
She was disappointed to discover how easy it was to follow Sherlock as he took his god-daughter Rosie Watson, and his son – her own nephew –Will, for strolls. She observed how he was with them, and connected how he was with her – gentle and patient, though always watchful. She noted how it was certain days he would take them out, and on this occasion – with Molly and John coincidentally both away at medical conferences, seemed to be content to be their sole caregiver. She noted the tenderness he had found in his manner and voice and how his humanity had seemingly come from the act of caring about and for another human being.
She thought how her greatest failure just may be her greatest accomplishment.
In spite of all she had done to destroy Sherlock's heart and his emotions, she found now, to her relief, that she had completely, utterly failed. If anything, what she had tried to destroy out of childish jealousy, she had re-awakened by trying to repeat that destruction as an adult.
There was hope for her after all. Someone had refused to give up on her. SHERLOCK had refused to give up on her.
And when, two years after her Waterloo at Sherrinford and their childhood home, Musgrave Hall, where she hadn't factored in the concept that her brother might feel COMPASSION for her, she held his son, her own mind racing and her heart seizing with unfamiliar sensations, only realizing later the significance that she had been the very first person to touch, to smile at, to sing to, and indeed the one to name John Victor William Holmes, she felt but did not recognize love.
She only knew that this tiny human with his father's features and his mother's spunk was the first person in the world she might… what was that word?
Her curiosity was piqued, and she obsessed over it for months, through their visits and their absences, through their calls and their silence as life pulled them away from her for two or three days at a time. Always they returned. Without fail, they returned, whether it was in person or just in contact on the phone.
So, on the day she happened upon her brother, on an outing with Rosie Watson and his son Will Holmes, she decided that it was time to reveal herself.