I think this is only a very small update to our picture of spree killer or terrorist demographics. We already know about the enrichment of terrorism with engineers, and Aum Shinrikyo had access to some smart generalists (neuroscience is not a directly deadly field). We also know that such folk are much more likely to succeed at super-simple plans, like this one, than at doing complex technological endeavours for the first time in the face of countermeasures.
How long will it be (if ever) before a typical bio-science Ph.D will have the capacity to kill, say,a million people?
That doesn't have to ever happen. Ubiquitous DNA sensors that identify deadly agents, DNA vaccines, ubiquitous surveillance at the planning stage, tripwires in synthesis machines, and so forth can proliferate. The typical bio-science PhD is pretty crappy (Sturgeon's Law), and likely to fail at something like making the smallpox virus unless there is a cookie-cutter script kiddy style approach pre-packaged. That might happen, but we also might see varied government interference that makes failure much more likely, just as interference at every stage of potential nuclear terrorism makes it impracticable (although that is eased by the rare materials).
Ubiquitous DNA sensors that identify deadly agents, DNA vaccines,
Sensors and vaccines all rely on that the pathogen is known, even coded. You could have a register of virulent genes, in order for it to be effective against hybrids, but even then it would be very hard to say whether a something is dangerous or not.
A Ph.D student in neuroscience shot at least 50 people at a showing of the new Batman movie. He also appears to have released some kind of gas from a canister. Because of his educational background this person almost certainly knows a lot about molecular biology. How long will it be (if ever) before a typical bio-science Ph.D will have the capacity to kill, say,a million people?
Edit: I'm not claiming that this event should cause a fully informed person to update on anything. Rather I was hoping that readers of this blog with strong life-science backgrounds could provide information that would help me and other interested readers assess the probability of future risks. Since this blog often deals with catastrophic risks and the social harms of irrationality and given that the events I described will likely dominate the U.S. news media for a few days I thought my question worth asking. Given the post's Karma rating (currently -4), however, I will update my beliefs about what constitutes an appropriate discussion post.