bill fly 
The certification reaction times have to consider each element - awareness and action, not necessarily in isolation, but in context.
There is no ‘trim runaway’ alert, thus the failure has to be deduced from other cues.
If autopilot engaged then the focus of attention could be on the unexpected autopilot disconnect, and flight path management.
Thereafter, as for manual flight, the main cue to abnormality might be stick force, inability to trim. This has to be related to the stage of flight, the flight path, and causation. In these context is critical; is the abnormality associated with configuration change, wind gusts, icing, speed, manoeuvre, all of which diverts mental attention from the main problem.
How long to read the above; more time than was assumed in certification?