Transporting Gongronema concentrate was always a tricky business. It was volatile under any circumstances - prone to violent sublimation upon exposure to pewter and highly unpredictable behavior when combined with the more aromatic Lamiaceae - but most troublesome at the moment was its tendency to react rather explosively with Floo powder. Severus, having allowed himself to borrow a couple of bottles of it from Horace's stores, had planned to ferry it safely home through Apparition. But Horace had a habit of storing everything in those silly glass-stopper decanters that were good for nothing but catching the light and leaking, and the prospect of Apparating with them (and the very serious mess that might result in his own parlor) had dissuaded him. Rebottling and magically sealing also posed more risk than he was willing to take, and so he was reduced to walking it all through Hogsmeade, guarding the bottles in the crook of his arm while trying to navigate the High Street without being jostled.
He should have been able to manage, too - the usual knot of people that always seemed to fill the pavements outside of the most popular strip of shops was nowhere to be found. But - as always - it only took one idiot child to muck things up beyond repair, and it was while he was trying not to step on a greedy little toddler making a dash for Honeyduke's that he crashed into the young woman standing just outside the door and the light tingling started on his arm where the Gongronema had soaked the better part of his sleeve - and quite a bit of her, too.
"Watch where you're going," he snapped, rearing back and juggling the one surviving bottle as he pulled out his wand to dry the stuff out of his clothes. He was more concerned with preserving what he could than with helping her; she'd be all right, provided she wasn't carting around any pewterware, mint extracts or Floo powder. "If you can't wait half a minute to stuff your face with those, Miss Cattermole, you might do it inside rather than waiting to be tripped over in the street like some daft troll."