Fig. 1

Flowchart of simulations. Two groups of bystanders, a) alone or b) in pairs, performed a simulated suspected OHCA-situation indoors at a fire station. Participants who performed in individual simulations also participated in dual simulations and acted in an assisting role. In their second simulation they only participated as assistant bystander. They had before the second simulation received clear directive that they were only allowed to be helpful with CPR if the first bystander asked them for help. They were not allowed to talk to the dispatcher, nor to fetch the AED or make any decision or suggestions, only to follow instructions