They were under orders Request that , if the city were to be attacked Attack , they should kill Killing all burghers of Swedish origin , burn Destroying the city and castle , retreat Escaping and regroup Cause_to_amalgamate in Visby , Gotland .

An agreement Agree_or_refuse_to_act was made Creating , that the burghers would leave Departing the northern city gate open Openness on the night before 27 May .