The match was actually a tag team match pitting AJ Lee & Tamina Snuka against the Bella Twins, not a singles match between AJ and Brie as reported earlier. They took a crowd vote beforehand to determine if it should be a singles or a tag match, and the tag match won.
During the match, AJ tagged out and went on the ring apron. While Tamina was in the ring, AJ started to hold her head and then slowly went to the outside before fainting a few seconds later. Tamina was looking around and noticed that AJ was missing, and she carried on with the match with kicks to Brie. The Bellas signaled to the referee that there was a problem. A doctor came out and gave the "X" signal, and then Brie quickly pinned Tamina with a school boy to end the match, so it wasn't called off as reported earlier. More officials came out, and AJ was attended to for 5-10 minutes. A referee and Tamina then helped a wobbly AJ to the back.
As noted earlier, WWE issued a statement noting that AJ fainted during the match due to dehydration, and is currently being evaluated by their medical staff.