walk behind vs walk from behind

[Daemon99]

1) I walked behind the Great Mall to get to the theatre faster.
2) I walked across behind the Great Mall to get to the theatre faster.
3) I walked from behind the Great Mall to get to the theatre faster.

Can someone please tell me if the above sentences are correct and mean the same thing?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Mister Micawber]

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The sentences are all grammatically correct, but synonymy depends on the geography.
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Native English teacher at Mister Micawber's

[Daemon99]

Thanks a lot, Mister Micawber!

Say, I was on one side of the Great Mall and the theatre was on the other. Going from in front of the mall would take me longer to reach the theatre. So I went from behind it. In this case, what would be the best choice?

Also, is going from in front of the mall correct?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Mister Micawber]

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You said that you are 'on one side' of the mall, so #3 does not work; the other 2 are OK.

Also, is going from in front of the mall correct?-- Not if you are on one side of it; only if you are in front of it.
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Native English teacher at Mister Micawber's