We do not understand 'trauma' as an event but as a psychobiological 'wound' evolved in relation to a variety of coupled psychological, biological, social, and other environmental factors (Nijenhuis and van der Hart, 2011).
References:van der Hart, O., Nijenhuis, E. R. S. and Steele, K. (2005). Dissociation: An ins ufficiently recognized major feature of complex post traumatic stress disorder, Journal of Traumatic Stress 18(5): 413-423.
Nijenhuis, E. R. S. and van der Hart, O. (2011). Dissociation in trauma: A new definition and comparison with previous formulations, Journal of Trauma & Dissociation 12(4): 416-445.