Okay, increasing levels of hint here.
Mild hint:
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×Does it matter in which order you do the two things you're thinking about doing?
Slightly stronger:
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×When there's more than one thing to manipulate, they can often be used together.
More explicit:
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×Use the mirror as an obstacle for the goblin to help you lead it to (16,12).
A useful strategy for doing the above:
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×Move to (16,12) yourself with the goblin chasing you, step off on a platform to the southeast, and then move that platform.
Hopefully that's enough to get you through.