So for this wrist grab, he's trying to twist backwards? But in what direction? Your backwards my backwards? Seems a tad vague.(and it seems to me he changed what he did from a simple block with an arm into an actuarial wrist grab again even though he abandoned that very act.) And he's using his arm to block the blade burst? I'll also add that must be the most uncomfortable wrist grab for him seeing as Taby's position means Metz's arm is inside his guard. Unless that's not a thing anymore for some reason. 

Also wouldn't the path of his dagger have Tablurath's right arm still in the way? Unless he pulled his arm back before he closed the distance.