What veekie and Unbeliever are saying, basically. To be fair, the 10-year old would have a lower chance of making the check, but only because his attributes are lower and he's untrained, leaving him to make a chance roll. However, his minimum roll is still 1 die, giving a 10-year old a 10% chance of successfully performing that surgery under the supposedly stressful conditions.
Or, hell... a two-year old in a full operating theater would have a 10% chance of performing a successful surgery.
Under the bottom line, if you want horror, you don't want swing. Swing means there is much more left to luck than is usual in the horror genre. What you want is monsters that are consistently stronger than the PCs, which means a relatively predictable RNG (i.e. a steep bell curve), with characters ultimately winning only through setting up a favorable situation and/or exploiting the monster's Achilles heel and/or a bit of luck. FATE-derived games aren't perfect for this due to the very meta nature of the mechanics, but they have the bell curve and the other elements in theory, so they're already a better fit than anything WoD has ever produced.
Hell, Exalted does horror better, say with a heroic mortals game (traditional horror) or even Dragonbloods (action horror). Alternatively, if you want the various WoD game lines' "you are monsters now", there's plenty of those (Abyssals/Infernals, any Akuma, Fair Folk, Abyssal/Infernal half-castes, demonbloods/ghostbloods/faebloods in descending order of badassitude).