Defense
 

I used to play TFT and had the wrong interpretation of the -2DX penalty because the penalty was applied on the next turn.

From what I understand now, the punishment should be applied in the next action.

WarriorA(DX13) attacks first, gives 5 wounds to WarriorB(DX12).
Warrior B fights (Dx12-2) because it's too late to defend, penalty cancelled. But hits and deals 5 wounds to WarriorA.

New round.

WarriorB(DX12) attacks.
Now WarriorA can fight (DX13-2) or defend.

Do I understand it correctly now. I know that should be the basics.

Re: Defense
 

You are correct, but note carefully that falling down from injury (ITL 118) only cost a figure their action from the current turn. So if they were higher adjDX than their foes they would have already acted and hence not lose an action from taking 8 hits that turn.

Re: Defense
 

This may seem a little misleading even though what you say is true.

From ITL, Page 118:
"A figure that takes 8 or more hits in one turn immediately falls down. If it has not already attacked, it may not attack that turn. It may do nothing next turn except stay down, stand up, or crawl 2 hexes. If it is in HTH combat it may do nothing next turn."

Yes. You do have an action the next turn after being knocked down. However, your options for that action are very limited.