I have no idea quite what the VPMC does, exactly, but I bet that it is more complicated than just being involved in 'the emotions'. Precisely what an emotion is, for a start, would be a good question to ask, and it certainly does not follow from this experiment that we need to go for any kind of dualist moral psychology, with on one side the rational calculating faculty and on the other the affective emotional faculty. True, when wondering whether to push someone on to a train line to prevent a greater loss of life further down the tracks, there are all sorts of considerations which we might take into account. Some are rightly concerned with the numbers of people involved in each alternative; others are to do with a personal feeling of responsibility; yet more are to do with fear or excitement or panic. In fact, there is a very good case for the view that all these scenarios seriously misrepresent what it would be like to face any such dilemma in reality. We certainly wouldn't be faced solely with a bare set of propositions, designed by the experimenter to point towards the single variable subject to the testing. Rather, it would be a complicated situation affected by all sorts of factors to do with one's current disposition, the way the surroundings are and are perceived and so on.
In short, scenarios like those touted by this kind of test seem to me not really to offer any significant information about ethical thinking 'in the wild'. While they are useful ways of illustrating particular ethical theoretical views, our reactions to them are hardly indicative of our likely behaviour. It is common, for example, for a student to tell me that they would 'obviously' choose to divert a trolley to kill one person rather than five. I have no idea whether that is true and, I imagine, nor do they. Are they really able to imagine what it would be like to be faced with such a situation? I can't.
People still interested in exploring this kind of thought-experiment might like to ponder the following teaser, by Michael F. Patton jr.:
There's an explanation of the example here. There is a variation on the example here.
On Twin Earth, a brain in a vat is at the wheel of a runaway trolley. There are only two options that the brain can take: the right side of the fork in the track or the left side of the fork. There is no way in sight of derailing or stopping the trolley and the brain is aware of this, for the brain knows trolleys. The brain is causally hooked up to the trolley such that the brain can determine the course which the trolley will take.
On the right side of the track there is a single railroad worker, Jones, who will definitely be killed if the brain steers the trolley to the right. If the railman on the right lives, he will go on to kill five men for the sake of killing them, but in doing so will inadvertently save the lives of thirty orphans (one of the five men he will kill is planning to destroy a bridge that the orphans' bus will be crossing later that night). One of the orphans that will be killed would have grown up to become a tyrant who would make good utilitarian men do bad things. Another of the orphans would grow up to become G.E.M. Anscombe, while a third would invent the pop-top can.