I find it hard to believe that any ground personell be it aircrew,handlers or an engineer would put such a thing in the gearbay or tiny knook and cranny of an aircraft for obvious reasons, but obviously it has happened and a very fortunate outcome, I dread to even think the carnage it could have caused, but without knowing the full truth I will refrain from making further comments .
Do we know what cargo airlines were operating that night.....Obvious ones UPS , FedEx , Titan , TNT................