Justin yanks his hand back in shock when Waterstrider snaps at it, his hand involuntarily forming a fist. And just like that, all the control had over the situation was gone. He could almost see it flutter away, right into Elizabethele's palm. "You stupid, stupid, animal!" he yells only half acting. Waterstrider had to improvise. If he had been obedient, Justin could have lied, wheedled, and connived his way out of anything he was asked of, and come out looking better for it. Fun while it lasted, but there was nothing he could do now.
"Thank you, my lady, for the chance to put my insolent mutt in his place." he says to Elizabethele in his most respectful tone. He has no clue how most of these pointy metal instruments work, so he'll settle for locking Waterstrider's wrists above his head and picking up a whip that looks just a bit the nastier side. "30 sounds like a good round number."
He'll begin to lash across Waterstrider's back. For the first few strikes, five or so, he'll mostly be thinking of the pragmatic losses of this, there's no way they'll be able to stay in the same room, Waterstrider will be physically weakened from this, there's no possible way for Justin to tell when control will come back to him. After that, he'll start thinking of what he's doing to his allies here. Brand and Waterstrider were both slaves, he couldn't possibly imagine what this action might be doing to them. How horrible it is to be on Waterstrider's end of the lash. With all the emotions going through his head, he tries his hardest to keep a stone face.
It feels like the lashing takes forever, and he can only imagine what it felt like to Waterstrider. In the end, he's breathing hard like he's angry, in truth he's it's a mix of shock and disgust at himself, his face leading others to believe his anger. "Had. Enough. WHELP!" He says each word slowly to prevent stuttering.
(Godmode permission apparently granted)