Andrea Juneau:
Correct me if I'm wrong, but wouldn't a lab that is working with anthrax have heightened security requirements? Locking doors and specimen cases? Alarm systems? Clean rooms? Guards? Certainly the lab would have to be a stand alone for ventilation and I doubt lower classes or even undergrads would be doing research involving anthrax. Right?
Undergraduates certainly wouldn't, but it's already established that post-graduates also study and research in the same spaces (this isn't entirely uncommon here in the states, I'm uncertain about the UK). Since we haven't actually seen the other lab at all, any requirement for anthrax research could be in place.
It seems likely that there would be restricted access to the lab, or the part of the lab, with anthrax, yes.
Safety and security standards are sometimes not all they're cracked up to be, though. Remember those Greenpeace activists who walked into a nuclear plant a few years back? And the 85 year old nun who got into a nuclear weapons plant? Those two cases were infamous for how easy it was to get in.