The math isn't technically valid, it's just for an example of the probability, but I'd point out that it doesn't suggest that 1 in 10 bullets would contact a drop. It suggests that only one in 10 bullets would even have water IN IT'S FLIGHT PATH, in front or behind it, during ANY portion of it's 2 second flight.
If that's even remotely close to true, even if it's pessimistic by a factor of 100, the odds of a bullet actually HITTING a drop of water are
exceedingly small.
They odds that they'd both be in the flight path ANYWHERE are about 1 in 10. The locations have to over-lap, not just both be somewhere in the flight path.
For example, the bullet takes up roughly 1/36,000th of the flight path. The drop of water takes up about 1/461000th of the flight path. The odds that they'd randomly be in the same place at the same time would be something like, 1:357000 or something.
Someone with more time will have to figure it if they'd like, I'm trying to do it between customers and pizza.