Set a flag in dialog called ATTACK

Then make a script:

[code]IF
ObjectFlagSet("ATTACK", _Player, _)
THEN
CharacterMoveTo(CHARACTERGUID_baddy_ID,_Player,1,"",0);
[/code]

This will make an enemy move to attack you after the dialog ends. Replacing the CHARACTERGUID with that of the enemy. You could also teleport them.