Let’s say you’re more fatalistic than utilitarian. Would you not then refrain from pulling the lever, under the belief it was meant to be as is?
Another factor that can change the dynamics of this situation — possibly make a liar out of some percentage of the 90% — is the difference between having it posed as a scenario that can be leisurely contemplated, or having it happen in reality with virtually no time to think. In this case, you’re engaging two different parts of the brain, each of which serves a different motive and purpose.
In the reality instance, with no time to think, your brain is likely to be dealing with the situation using the fight or flight mechanism of your brain. This is located in the brain stem. The rational and thinking part of the brain is located elsewhere, north of the brain stem. Insofar as the brain stem serves as a sort of gatekeeper prior to reaching the rational part of the brain (the act-now-without-thinking version of the brain), it’s conceivable one would turn and run in order to avoid the prospect of witnessing either outcome. After all, neither outcome is something anybody really wants to see.
If, on the other hand, there was time for this dilemma to move beyond the brain stem and reach the rational thought region, it’s conceivable one would freeze and do nothing, due to the confusion of cognitive dissonance — to wit: there is no right answer even though the rational part of the brain urgently wants the right answer. Such a circumstance can create analysis paralysis.
This is why actions speak louder than words. You can’t trust what people say they would do in this situation, because it doesn’t carry the same dynamics as the real situation.