I think we may need to repurpose an existing word. I've been searching for such a word with adequate connotations and historic usage to suggest what you describe.
I offer heresiarchy, or a similar form such as heresiarch, turning toward its etymology more than its primary usage:
he·re·si·arch (hə-rē'zē-ärk′, hĕr'ĭ-sē-)
One who originates or is the chief proponent of a heresy or heretical movement.
Following to the 2nd sense of heresy: a) A controversial or unorthodox opinion or doctrine, as in politics, philosophy, or science. b) Adherence to such controversial or unorthodox opinion.
(American Heritage Dictionary)
Etymonline states "The Latin word is from Greek hairesis 'a taking or choosing for oneself, a choice, a means of taking; a deliberate plan, purpose; philosophical sect, school,' from haireisthai 'take, seize,' middle voice of hairein 'to choose'."
In my personal view, the questions we have the clarity and courage to formulate are often the first step toward a "choosing for oneself". This tightly links questioning with self-determination. Questions lead to assertions, then to challenges against an established social order (not just a religion). Those who take this path risk the label of a "heretic", though in modern usage "heretic" and "heresy" are more figurative and far less pejorative. (And the danger is usually to one's reputation, not to life or well-being.)
This usage of "heresiarchy" by Kim Stanley Robinson in Galileo's Dream (a 2009 sci-fi / historical fiction work) may be applicable, describing the "categories" of heresy in progressing severity:
from slight suspicion of heresy . . . to heresy . . . to heresiarchy, which meant not only being a heretic but inciting others to heresy as well.
I interpret "heresiarchy" as the most extreme form of heresy – that which risks danger, as stated in the OP's question. (See the Etymonline entries containing arkhos, which gave rise to arch/archi/archy as both a prefix and suffix.)
Below are a few historic contexts I found of "heresiarch", associated with people who are emblematic of revolutionary potential, or risking personal danger:
- ". . . implicitly labeled Galileo as the worst kind of heretic, a founder of a sect and therefore an inventor of heresies, a heresiarch."
- The Roman Inquisition: Trying Galileo, Thomas F. Mayer, 2015, see Google Books.
- ". . . he thoroughly blackens the status of theologians and says that that heresiarch Luther is a holy man, and that it is not surprising if Luther errs in some matters, since saints such as Augustine, Jerome and others also erred."
- Quoted in Clément Marot: a Renaissance Poet Discovers the Gospel, M.A. Screech, 1994, see Google Books.
- "Leaving the place he had considered the Mecca of physics was as much a confession of failure to him as it was the act of a heresiarch to the faithful at the Cavendish." [Meaning Cavendish Laboratory in the Department of Physics at Cambridge University.]
- Love, Literature and the Quantum Atom: Niels Bohr's 1913 Trilogy Revisited, Aaserud and Heilbron, published 2013 – a figurative modern usage describing the 20th century physicist Niels Bohr. See Google Books; note that Einstein also appears in this context, and Einstein was quoted by the OP.
- "In order to achieve such an upset of power relations at the heart of the philosophical field, and give a form of respectability to stances that were heretical . . . Heidegger had to combine the 'revolutionary' dispositions of a rebel with the specific authority granted by the accumulation of a considerable capital within the field itself. . . prophets, as Weber observed in the case of ancient Judaism and of heresiarchs in general, are often defectors from the priestly caste. . ."
- The Political Ontology of Martin Heidegger, Pierre Bourdieu, 1991, see Google Books.
The last is a wise observation; note that Martin Luther, Giordano Bruno, and Erasmus were all Catholic priests who challenged the Church's authority from within their "caste".
I recognize that the single word heresiarchy may be an imperfect answer, as it doesn't clearly and exclusively signify the act of questioning. Heresy often consists of strong, unyielding assertions – it is statement, not inquiry. However, the OP muses that in our current era, "merely declaring truth is no longer sufficient."
I'd like someone to discover a less obscure and academic name for “the act of asking a dangerous question”. I believe that heresiarchy could do in a philosophical work, but I doubt it would be readily adopted by others. I'm curious for feedback.