There's diminishing returns to intelligence and inherent unknowns to all moves the serf can make. The serf somehow has to evade detection, which might appear to be effectively impossible given the unknowns of how detection may take place.
Even if there was, there's no reason at all to think those returns are anywhere near the upper limit of human intelligence.
Wheels are far more energy efficient and faster than legs, steel more resilient than tortoise shell or rhino skin, motors more powerful than muscles, aircraft fly higher and faster than birds, ladders reach higher than Giraffes much more easily, bulldozers dig faster than any digging creature, speakers and airhorns are louder than any animal cry or roar, ancient computers remember more raw data than humans do, electronics can react faster than human reactions etc.
To be so sure intelligence would be some exception seems like hubris.
I don't see general intelligence as a specialized skill.