What's the problem?
(...) Keep in mind that editing within the queue will be a unilateral Looks OK vote, so be careful with edits that just make minor improvements ("rearranging deck chairs on the Titanic").
Edit from inside the review counts as unilateral Looks OK and/or kicks the post off the queue, i.e. no one else gets to decide from the queue.
Why is it designed that way?
For rare cases where edits would actually salvage the post, without transforming the meaning, examples:
Salvaged a link-only video post, while not adding anything else to what the author said.
Added Wikipedia links that confirm the answer (it may not have been apparent the Yak-42 is a jet-liner).
Note: typos and formatting are never a reason to send the post for review; anyone -- even unregistered users -- can edit / suggest an edit to fix those issues.
I want to fix typos and formatting while I'm reviewing
Click on the post's title (no need for a middle-click; shown below), and it will open in a new tab.