he has overpair and and backdoor to straight, if he is a good reader and knows opp is on AK, he wants opp to call cause is in front and win 3/4 times. 5$ bet in 12 pot is ok, but also is 50% of our stack so will prob induce hand strenght to opp, can also make opp fold cause if he call he is all in and hold nothing no so he may not risk his stack on air.

99 bets cause he has on what to bet, the 12$ pot means he's double his stack so he would like to get the pot on flop.