So, he'd run out of snowballs, meaning there was no longer anything going on in the way of a distraction, and Kyle didn't want to waste time on trying to orchestrate another one just yet. He needed to get this potion brewed, and brewed quickly... but brewed well.

Having caught the potions vials as they flew at him, Kyle spared the time to double check that every ingredient was present and correct, before stowing them away in his pocket, so that his wand hand was free. That done, he went ahead and cast a customary "Scourgify," on the cauldron, before applying a Supersensory Charm to himself, like he had in the first challenge. Given that he was working at night, it would help him to see what he was doing with his potion, and, if necessary, to get some kind of advance warning as to if he was about to be on the receiving end of an uppercut from a flailing branch. If he could hear it, he'd at least have a chance of ducking out of the way, or raising the shield.

After bracing himself, Kyle hoisted up his silver shield again, and brandished his wand at the Whomping Willow.

"Immobulus!"

He didn't waste time checking to see if the spell worked, and instead chose to assume that if it worked, it would not work for very long. Perhaps, though, perhaps it would grant him a few precious seconds to reach the workstation.

As soon as he cast his spell, Kyle held his shield up to protect himself, and dashed forwards to the workstation. Once he reached it, he set his cauldron down and pointed his wand inside it again.

"Aguamenti."

... Why did it feel like it was taking ten years to fill up?