While reading a grammar book, I learned を may mark a.) a starting point of where a movement occurs, or b.) mark a location where a movement occurs. Examples:

a1.) 車{くるま}降りました{おりました}。(He) got out of the car.

b1.) 危ない{あぶない}なあ!歩道{ほどう}走る{はしる}なよ!(That's) dangerous! Don't ride on the sidewalk!

However, other particles serve similar functions, and I don't quite understand the differences in usage. For example,

a2.) 車から降りました。

b2.) 危ないなあ!歩道走るなよ!

Why would someone used を in the first sentence instead of から? Why would someone use を in the second sentence instead of で? How do the meanings in these individual sentences change between one choice over the other? When to use を in sentences like these and when to use different particles?

marked as duplicate by Chocolate grammar Aug 21 '18 at 2:07

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