

Not standing and walking in front of a car is basically cop 101. “Routine” vehicle stops are one of the most potentially dangerous things cops do, there’s all of the unknowns of who is actually in the car and how they’re going to react, what can happen if they try to flee, dangers from passing traffic, etc.
So they always approach your car very carefully and absolutely do not walk in front of it if it can be avoided.



I’m sure it’s more complex than I’m making it out to be, but each gas in the air has its own freezing/melting boiling/condensation/sublimation points, so I’d imagine you could just kind of take advantage of that
Basically just cool it down to x temperature at y pressure, and all of the carbon dioxide should be solid, the oxygen a liquid and the nitrogen still a gas, and they’ve all sort of separated themselves out. Fish out the dry ice, siphon off the oxygen, and you’re left with nitrogen.
Might need to do a couple more rounds of that on each of those to account for other gases in the mix depending on how pure you need it to be, but in theory I imagine it could be that simple (again in practice I’m sure there’s probably a lot of details I’m missing)