Even if you consider running consistently over a long period of time?
Also, my hypotheticals were meant to be such that you wouldn't take even vanishingly small chances. If you are willing to, then I failed in my argument.
The chance of a party with 1% support getting 300 or more seats out of 600 is roughly on the order of 0.04^300.* This number is so small that you're probably better off worrying about a literal biological virus that turns people into fascists.
*The factor of 4 comes from the rate of growth of the central binomial coefficients.
Also, my hypotheticals were meant to be such that you wouldn't take even vanishingly small chances. If you are willing to, then I failed in my argument.