[Semiapies]

"How do we prevent this from being attempted again?"

"We" won't, bluntly enough. Nor will hyperparanoia do anything about the next stunt. What do you do when a lunatic swallows or rectally inserts some explosives?

The answer is that you accept that there are reasonable measures and unreasonable measures. Use only reasonable measures. Accept that there is a finite risk of someone getting past those measures. Recognize that you're more likely to die while driving to an airport than in flight from all causes, not merely the extreme outlier possibility of someone deliberately trying to kill people on your flight.