Nooooo it wasn't like that LOL.
But I just hope he doesn't think I ditched him or anything like that. We lost the battle and got rezzed at a shrine and that's about when I may have succeeded in typing "OMG" a few times in the chat box I couldn't see. I'm hoping he didn't interpret that as "OMG this is horrible, I'm leaving!" when it was really "OMG, I can't see the freaking chat box or anything and I don't know how to get them all back!"
I kind of recall how his armor looks like so if I'm hanging out at Gadd's and see him, I'll ask if it was him. The party I later did Shards with have made a habit to joke around the camp fire there so I may be there anyways. There's no need to log in and hang out there just to look for my partner. But hopefully I catch up with him and explain what happened.
From now on when I join a party, I'll put one or more of the names temporarily in my Friends list just incase anything like this happens again. That way a record of their username will be there when I log back in.