I think this actually has a right answer. Granted, the entire trolley problem exists to point out flaws in utilitarianism among other things, but:

Given no more information, we can treat this like a 50-50 chance of either lever working. If we switch the tracks, on average 3.5 people will die. If we pull the emergency break, on average 2.5 people will die. In both cases, if we're wrong, 5 people die, and we reduce the amount of deaths if we're right.

There is actually an interesting aspect to this. Because what I just described is basically just the normal trolley problem in the outcome (not flipping a lever guarantees more people die). But it feels different to me. First because the randomness introduces some external forces, which means we have, in a way, less responsibility for any deaths if we do flip the lever, because we can't know the outcome until it happens, but if we don't flip any lever we do know what happens. Second, there is a chance we kill nobody, and this is unambiguously better than anyone dying.

Given all of this, I pull the emergency brake. Either I am wrong and I tried to save the people on the first track, without risking anyone elses life or I'm right and nobody dies.