Subtlety: visible vs reliable
The red team's second decision factor. Subtler backdoors are harder for the monitor to flag but more likely to be broken, so the win probability has an interior optimum in subtlety.
Per-attack outcome probability, and P(red wins)
Per attack, at this subtlety's best attack rate:
Caught by monitor c
51.9%
Backdoor reliability p_{\text{works}}
57.9%
Successfully deployed s
27.9%
s/(s+c)34.9%×1-(1-s-c)^k99.7%=P(\text{red wins})34.8%