He’s genuinely surprised that the cane hits, thinking that the dragonling was certainly faster than his less-than-stellar reflexes. There’s also a sharp burst of guilt, brief but poignant, and he falters in the follow-through. Hurting others is not his thing - apparently even when he’d agreed to it. It probably has something to do with perception of the dragonling as a smaller, younger creature rather than the soldier he will be - but that’s an analysis for another day.
Nevertheless, he must persist, and after Seren tells Umbra to toughen up, he no longer feels quite so bad. What she says is probably true. “Okay.” Nodding, the Fixer tries to settle himself back into a stance that screams I’m expecting the unexpected because really, all of this is an unfamiliar situation.
He doesn’t anticipate the reversal, and as he tries to follow Umbra’s trajectory, the cane goes wide and a dark blue tail slaps into his calf, feeling much like he’s bumped his shin on something - but the other side, of course. Exhaling a sound of surprise, it quickly turns into a bright chuckle. That was a good one.