User blog comment:B214/Chapter 499: Gray & Juvia/@comment-7418318-20160829105640/@comment-4933386-20160829110444

Hypovolemia is also another way to die, because if they stab the heart... well obvious Juvia can't do anything to heal Gray and therefore both won't survive.

I don't think Brandish was there to do anything as she walked away and Invel saw her went "that way". Unless she already predicted this was gonna happen she intervened somehow.