There is no real critical engine on a ducted engine because there is no real thrust line like on a prop.
There is a critical engine however on the aircraft you mentioned.
The critical engine is located on the upwind wing on a crosswind takeoff and landing.
On a crosswind an aircraft tends to weathervain into the wind, now imagine losing an engine on that side. Its going to be uglier than losing the engine on the downwind side of the crosswind
Hope it helps.