Biden: Gabby Giffords ‘Was Shot and Mortally Wounded’

We all make gaffes and we aren’t always aware we made the mistake,  but many times we catch our own mistakes  immediately and correct ourselves.  I find it amazing  how often Biden makes gaffes and doesn’t catch his own mistakes and correct himself.  Does he know what mortally wounded means?  Is it a gaffe if you’re just ignorant?