"The bullet traveled across his pelvis, fracturing bones, injuring internal organs, and causing severe bleeding," the statement said.

The title is a partial quote from:

How being shot in the hip can be deadly

Because this assault rifle round didn't stop in his pelvis but traveled "across the pelvis fracturing bones, injuring internal organs" this is why this could be why he is still considered in "Critical Condition" because of the organ damage in addition to bone fractures. Also, depending upon 'Where' it hit his pelvis it could interfere with his walking in the future too, if it hit directly in his ball joint so his hip and ball joint might need to be either repaired or replaced before he can walk properly too. So, just saying "he got shot in the hip" is much more serious than one might imagine at first.