The Cyber Security Forum Initiative (CSFI) held a cyber conflict escalation exercise at a conference in Stockholm, Sweden to discuss international collaboration on cyber security issues. The exercise involved two scenarios - an attack on the UK financial system and an attack on US oil refineries. A panel of experts from Sweden and the US participated in discussions after each scenario. In a post-exercise review, the panel identified lessons learned around improving the scenarios and discussion. Areas for scenario improvement included ensuring political and military contexts were accurately captured. For discussions, lessons included the need to specifically engage various international bodies and expand the range of panel expertise. The exercise reinforced the importance of pre-established relationships and ongoing dialogue to address pressing cyber challenges.