Haphazard hand-wavey timeskip
[Making their way to the clinic had been surprisingly difficult, especially when Ciel is used to defending himself with firearms and a big, bad demon. The measly knife he wielded required him to get into close range combat, definitely not one of his strong points, but thankfully Madam Red was more than efficient with her scalpel and knife.
And if Ciel was a bit heartless in using one or two bystanders as distractions for the attacking beasts as he and Madam Red fled, well...
They'd successfully barricaded the clinic once they got there, letting in some survivors and putting them to work at defending the perimeter. He even directs some to start lining the ledges and windowsills with flammable liquid, just in case.
Ciel isn't nervous about Sebastian not reporting in, at least not yet, trusting the demon to do a through investigative job before reporting in. But when the minutes start turning into hours, Ciel starts to pace, making it seem like he's checking on the other survivors when he's really using it as an excuse to peer through the sliver of window that's still exposed. Where the deuces is Sebastian?]