The Hamlet Project

This is a weirdly complicated sentence for what seems to be a fairly simple thought – which is that sometimes it pays to be rash and/or indiscriminate.
But the thought bounces hither and yon.
Like, what is “let us know” doing in the middle of this sentence?
And what is rashly related to, grammatically speaking?
Is this fragmented phrasing suggestive of his fighting heart that would not let him sleep?