The first scene to be filmed was the scene where Wilhelm and Erik run away and fall down. The actor, Edvin Ryding, stated this on his Twitter.
According to Evdin Ryding (Wilhelm) Twitter, the scene where him and Ivar Forsling (Erik) run away and fall down was an accident. Edvin didn't have traction on his shoes and fell, accidentally bringing Ivar down. Ivar ending up bruising his hand.