Note the section "exponential dose effect and single-hit process". And try not to jump to conclusions about what may or may not be or have been a "consensus opinion" by references to "threshold models".
As Kellerer points out (p 346):
Threshold considerations provide general conclusions without actual commitment to the reality of a threshold. Biological objects do not exhibit defined thresholds in terms of energy deposition in certain target structures. More complex models have therefore been considered in the past, and they have been revived from time to time.These approaches postulate a spherical target region, sometimes the cell nucleus [nominally 6 micron], sometimes a smaller structure [1/2 or 1 micron]. ...
The approach may appear attractive. However, there are hidden assumptions and hidden difficulties. First, the selection of the reference target is uncertain. The only reasonable choice may be the entire nucleus of the cell. ... [Secondly] It is assumed that the effect probability depends merely on the specific energy in the reference region; no account is taken of the fact that equal values of specific energy may be associated with different distributions of energy imparted within the target region. ...
Kellerer notes (p 354) that from a negative logarithmic survival probability with respect to absorbed dose one obtains the RBE for neutron dose as 1/sqrt(D_n). He says
This relation, the inverse proportionality of neutron RBE to the square root of neutron dose, has been a guiding principle in experimental studies not only of cellular but essentially of tissue effects, such as radiation tumorigenesis. The investigations have uncovered high values of RBE of neutrons that agree with the microdosimetric considerations, while the exceed substantially that value 10 of the quality factor utilised for purposes of radiation protection [AM Kellerer & HH Rossi, Cancer, A Comprehensive Treatise, Vol 1, 2nd ed, FF Becker (ed), Plenum, NY, 1982, pp 569--616]. ...In spite of the broad experimental evidence for [the above equation], one cannot exclude the possibility that certain radiation effects have a more complex dependence on specific energy. ...