When you are adding the menu slug as
edit.php?post=706&action=edit, it is adding in the url after admin.php considering it as a new page in admin dashboard (general behaviour of add_menu_page())
So, you should give a fully qualified url instead. I think, admin_url() should help.
Try adding
admin_url('post.php?post=706&action=edit')
Or
admin_url('edit.php?post=706&action=edit')
instead of
edit.php?post=706&action=edit
as menu slug.