Very sad news.
It does raise questions about what protection is available for UN contract staff. They are sent into areas where hostilities take place or are likely to occur, which is why the UN is there. Therefore they should receive adequate protection.
Are they issued with body armour and firearms? What sort of security is provided for their residences, offices and hangars? What sort of perimeter defences are there for airfields? There should be safe zones around airfields to prevent short range attacks on arriving and departing aircraft.
What sort of life insurance/ compensation is provided? Ordinary life insurance policies are usually invalidated if the insured ventures into lawless or war stricken areas.
Someone needs to do some thinking and provide some answers! Anyone considering a job with a contract company needs to get these questions answered before hiring on.