Cass smiled as he saw Katie, nodding. 'I offered already,' he said, not sure if she'd heard him, there had been a bit of a noise in the room at that time. 'It's hard not to, isn't it, when it might make such a difference.' Personally, he hoped the bombs wouldn't kill anyone, just arouse enough attention to get people outside. Well possibly with the exception of it landing on Rodolphus or Bellatrix's heads.
'You?' he asked, not sure if she had offered or not, he'd been a bit too focused on Percy at the time.