As a licenced engineer i find it very sad and somewhat laughable that some people would suggest that any engineer would allow an aircraft with a serious defect to leave the gate knowingly. There are strict guidelines which govern whether an aircraft is despatchable or not..... On a daily basis engineers carry the burden of responsibilty and always have safety as their number one consideration... Nobody wants to see this type of thing happen.
My best wishes and thoughts go out to all involved in this tragic accident.