Hird is a trained stock broker and would be familiar with the maths I outlined. Basically he is betting on a horse that has a 100-1 chance of winning but only paying $10 and if it loses he has to pay the bookie another $50. It's not a rational choice. Even if he thinks the worst case scenario is he won't be able to work again, he would be better off just saving money on legal fees. This is why I say it isn't about money or livelihood it is purely about his reputation and legacy etc.I don't follow the 'maths' you are talking about.
A guilty man, with something to hide, continues the charade until all hope is gone.