Tension pneumothorax or haemopneumothorax is a clinical diagnosis. Plain radiography is not advised to confirm the diagnosis and may delay definitive treatment. Unstable haemodynamics is one of the prerequisites for the diagnosis. We report a case in which the patient suffered from haemopneumothorax with all the typical radiological features of tension, but without any clinical sign of unstable haemodynamics. Close monitoring of patients suspected to have pneumothorax is recommended, especially in the radiology suite.