Powas targeted ATTACK = 7 > 6 = Snake's DODGE, so Snake failed to dodge it.
By the rules, ATTACK will do MEDIUM damage and it will be on target.
Calculations for the targeted part are:
(4 x 10) + (2 x 10) + 15 (randomly set) + (3 x 10) = 105 points
To hit a lungs Powas need 50 points (for upper body) + 25 points (for lungs itself), and he has 30 points more than needed, so he hits the target.
Lucky to snake this wasn't full damage attack due to his dodge used. So no critical damage, just big bruise.
Snake lose 23 HP. Powas still have initiative.
Snake HP = 117
Powas HP = 148