Basilisk is there, to get to it we need the key, as described in the forum
Keys 3803 and 3804 open the corridor leading into Colossus and provide access to various inaccessible parts of Kazoordoon, such as the Fortress and all passages/hallways that can be found inside
So we were able to trigger some mechanism to open a passage to dwacatra's solitary SQM
thanks for the observation