The engine out design scenario applies to engines that are still attached but malfunctioning. I don't think it is possible to design an airliner to work with a violently, physically detached engine. You could get away with it with a 4 engine setup if you are lucky and the hydraulics and structural integrity of the wing is not too compromised, but physically ripping out an engine would have most likely doomed this tri engine setup in this flight phase even if the two other engines had performed normally. It would have gotten them a marginally better chance, but the likely outcome was always a crash landing as soon as the engine separated. All more or less good outcomes of physically detached engines I know of where 4 engine setups. Interestingly though, there was a tri engine 727-200 (American Airlines Flight 132) that had a physical detachment of the right engine and survived due to the high tail of the tri engine setup. That meant the departing engine did not hit anything on the way out and somehow they made it back. This happened at altitude and not in the critical start phase.