I accidentally hit Alt F4 while in a PvP match (I had a modifier binded to Alt and was swapping pets), I reloaded GW2 immediately and had it running in sub 10 seconds, but to my horror I couldn’t rejoin the PvP match no matter what. I was on the same character.
The score was about 40-100 when I disconnected so there was still a lot of time left.
The PvP menu has “Leave Queue” greyed out and “Matchmaking in progress”. Eventually I just got dishonored for 15 minutes.