Which of the following actions is NOT part of care under fire?

In a combat situation, "care under fire" refers to the actions taken by a caregiver while under enemy fire, prioritizing the safety of both the casualty and the caregiver. The primary focus during this phase is to ensure that the caregiver can effectively protect themselves and the casualty while also returning fire to defend against threats.

Applying a tourniquet and providing cover while moving the casualty are critical actions that align with the principles of care under fire. Both involve immediate interventions to control life-threatening conditions while maintaining awareness of the ongoing danger from enemy combatants.

Treating an open chest wound, on the other hand, typically requires a safer environment to minimize risk. This kind of intervention involves more intensive medical care and attention, which would be inappropriate to perform in the chaotic and dangerous environment of care under fire. Thus, this action does not fit within the scope of what is feasible or advisable during this high-risk scenario.