That relative risk reduction is very signficant, not just statistically signficant, it is very practically signficant too.

Sure, but the sample of confirmed positives is so small that it might not include some important subgroups. If only 1 at risk person in the placebo tested positive, and 0 in the vaccinated group did we haven't learned much.

How much longer? There is significant benefit to rolling out massive amounts of vaccine immediately. I know that any scientist worth their salt will almost always claim that more study is warranted. But we're playing against a clock measured in human lives right now

And if this vaccine doesn't work or has nasty side effects, or even ends up killing people, most people will be very reluctant to take it, or any of the next better vaccines, and that would cause even more deaths.

It's a hard problem, and even though the clock is ticking, we also need to get it right the first time.