It aint the engines or lack of em that are gonna put you in the drink.
True, unless you lose too many of them... If you start with 4, you can afford to lose 1, and can keep it flying with 2. If you start with less, you can afford to lose less...
However, 4 engines also bring 4 generators, 4 separate full-time hydraulic systems, 4 sources of bleed air for pressurization... Loss of any one of those is usually not a big deal, and loss of 2 is controllable. Again, start with less, and you can afford to lose less...