critical failure rolls

franz keeps rolling critical failures, thats 4 in the past 10mins alone, and 2 of them consecutively. i dont mind him rolling critical failures but statistically rolling 1d20 it should happen only 5% of the time, whatt are the odds that of the 7 rolls he made 4 of them were the same roll, thats a probability of 57.4% it doesnt feel like a coincidence