Assuming that this is in fact some type of safety lockout preventing the car from starting due to some problem in the fuel delivery system, I am reluctant to bypass it and jump the starter directly for fear of damaging the engine or causing injury to myself.

Let me ask the question in a different way:
What would cause the fuel pump to run continuously upon initially turning the key to the run position, with audible flowing of fuel through the regulator and back into the tank?

__________________
Robert Fini

'12 ML350 BlueTec, 87k
'06 E320CDI, 270k
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 69k
'97 C36AMG, 313k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)