TL;DR:
We don't know how Suki/The Scribbler got her powers. It's suggested she, like a few others, just had them. She changed the machine, which led to others becoming stronger.
Long Answer
The Scribbler was based off a graphic novel written by Daniel Schaffer:
Usually we could go to the source material for some detailed information on it, but it's actually a very short comic - a one-off story of 96 pages. I think the best explanation I've seen of it comes from IGN's review of it, where they commented:
At less than a hundred pages, The Scribbler doesn't give much of a
background story on any of its characters. The book starts in the
middle of one of Suki's sessions, as she recalls her first check-up,
where hints of her insanity emerge, then jumps to the story. Some more
information on how she and the others ended up in the asylum would've
been welcome.
You can view a seven page preview of the comic online and see for yourself how quickly it jumps into the story (treatment begins on the second page!). Given this, it can be difficult to work out exactly what is going on. As the story itself says:
Female Officer: Why don’t you tell me what happened, from the
beginning
Suki: That’s not always the best way to tell a story
However, Daniel Schaffer has this information on his website:
Meet Suki. She has multiple personalities. She hears voices. She's
crazy... but not for long. Suki is almost ready rejoin society thanks
to the Siamese Burn, an experimental machine which is burning those
voices away one by one. All except for THE SCRIBBLER; that one is
getting louder. For a voice, it doesn't talk much - instead, its
messages come in the form of backwards scribbles.
And what it's scribbling is "Let me out!"
That is the premise behind THE SCRIBBLER, a 96-page original graphic
novel by writer/artist Dan Schaffer (INDIGO VERTIGO, DOGWITCH) out
this November from Image Comics.
"THE SCRIBBLER is not a superhero story, but it might be superhero
story in negative," explains Schaffer. "The heroes are all nutters,
characters with secret identities so secret, even they don't know
about them! And they're engaged in a fight between good and evil that
might not even exist. It's not so much a dissection of superheroes
themselves, because this is really not a superhero book, but it is an
exploration of archetypes, the reasons we invent them, and how we use
them to create and fight invisible wars."
Using this, and our knowledge from the novel and movie, we can piece some things together. Suki has got multiple personalities and The Siamese Burn effectively destroys the extra personalities one at a time, via an electroshock-esque treatment - but what are the extra personalities? That's effectively the question that permeates throughout the entire story. Is The Scribbler the real her, or is it something else? Throughout her treatments, The Scribbler takes control as she doesn't want to be erased. As The Scribbler, she modifiers the machine (we don't know how) to perform the opposite effect. Rather than erasing them, it brings them to life. This is what helps the other patients.
This means that someone like Hogan, who just wants to help people, develops incredible powers such as the ability to float, see the truth. Similarly Alice (i.e. Michelle Trachtenburg) becomes a darker, evil being. Ultimately, this is about as much context as we are given. To give some information on the metaphorical why behind how the machine works, we can look at this interview with Dan Schaffer:
Beckett: I would think creating a book dealing with psychological
disorders would be a daunting task. How much research did you do for
The Scribbler, and is the technique used for rehabilitating Suki’s
multiple personalities something created by you whole-cloth, or did
you come across it in your research?
Schaffer: The Siamese Burn Therapy is a metaphor for the machine-like
nature of authority or the general rigidity of the modern world. Seems
like the more free we get and the more enlightened we become, the more
we tie ourselves up with rules and regulations. The idea of a machine
that resets you back to normal mental health displays a certain
arrogant assumption that the people who made the machine know what
mental health is. I’ve spent a lot of time researching various forms
of psychology, I live in a house with psychologists so the place is
filled with text books, but The Scribbler isn’t really about that
stuff. It’s all just a metaphor for life in the twenty-first century
where everyone is expected to think in a particular way or do their
jobs by the book without question, and this kind of
spreadsheet-mentality leaves no room for personal style. Individuality
is slowly becoming outlawed. To me, that’s insanity. Surely we don’t
want to live like ants, right? The Scribbler is basically saying that
the more you suppress people’s creativity, the more creative they will
become. It’s an optimistic book looking towards a world where the
people with all the answers finally realise they don’t know shit and
stop hassling the rest of us with their theories.
In other words, the central theme of the book is to be yourself and embrace your creativity and individuality - the how and why of the machine wasn't that important to Schaffer. It's what it makes the characters become that is.
Conclusions:
So to summarise, as best as I can see it:
- Suki/The Scribbler is special and has the ability and knowledge to modify the machine. We don't know how. Schaffer's quotes suggest that it's her secret personality and that it's just stronger than she knows - that's all the depth we get it unfortunately. Whether the machine made it stronger, or it was strong to begin with, is also unclear.
- By modifying the machine, she enables everyone to become who they truly are, i.e. to give power and strength to their inner personalities.
- As a film based on a very short graphic novel, there was never a long, detailed back story to turn to.
- The graphic novel has fairly mixed reviews (as does the film), with the biggest criticism being style over substance - i.e. everything looks pretty and the cast (in the film in particular) are great, but the plot is lacking and incomplete.
