I am glad you are Ok.Experience like that is never good,but everything that doesnt kill us makes us stronger.And wiser sometimes.
There is no such thing like a warning light on the dash that the airbag did not deploy.it is a warning light that the SRS(airbag) system was triggered in some way and is no more active at the moment.BMW has a smart airbag system,and I dare to say very efficient.Most cars will deploy airbags at impact at any speed over 20-25 MPH.But such event as having a "date" between your head and the deploying airbag is not so innocent like it sounds.Your head is travelling with -20-30-50G negative acceleration and form the front comes the airbag with 4-5 times this speed.Never happened to me and I dont feel it is going to be good.
So,the BMW airbag system will take a different measures given the speed, the negative acceleration and the direction of travel of the car.At low speed at may trigger the seatbelt pretensioner only and not the airbag(s).At higher speed it may trigger the first stage of the airbag only,causing less strength of the impact.At higher speeds both stages of the airbag will be deployed+the curtain airbags.The passenger belts/airbags will be deployed only if there is a passenger 50lbs or more on the seat.My guess is your bruises are from the seatbelt.Of course there is always a chance that the airbag failed to deploy,but I highly doubt that.
i bought mine '12 X5D after it was in severe accident.my guess is that it went out of the road at speeds 60-90 Mph.All wheels were bent,all airbags deployed,some damaged suspension,etc.I am pretty sure all passengers were safe and sound.There are a very few cars on the market now that could offer such a protection,passive and active.The body structure is made of wisely engineered and heavily reinforced elements.Unlike the Japanese cars,there is a real metal in this panzer