im got stuck at new map derelict mansion

please unstuck my characther
nick : Lquen
lv 90 stormweaver

got stuck at boss arena and cannot kill the boss cause he is outside arena, i cannot go outside arena cause door closed and cannot using teleport cause it count as boss fight. and cannot use reset on checkpoint option on menu too please help me

https://imgur.com/a/tWjBW2k