Only an SLF so don't really know what I'm talking about, but since this whole incident came about with the initial failure of just one engine, wouldn't 4 engine planes in theory have twice the risk of this occuring than a twin?!
The maths seem incontrovertible
On the other hand, I'd guess there are a lot of silent motor outages that just remove an engine's thrust without any damage to anything outside the engine. In those cases a 4-engine plane ends up with 3/4 of its engines running, 3/4 of max thrust etc.
So, assuming that uncontained failures are very rare compared to silent failures, 4 engine planes have an advantage; if they are not so rare, then maybe 2-engine planes have an advantage -
Edmund