This paper presents the design and implementation of an immersive Virtual Reality (VR) training system developed to enhance the preparedness of corporate first responders in managing medical emergencies. The training platform leverages wearable VR technology and multi-user interaction to simulate complex situations in the workplace, such as cardiac arrest and polytrauma, with high visual fidelity and emotional realism. Through a mixed-reality interface, trainees interact with virtual patients aligned to physical mannequins, facilitating procedural accuracy and spatial awareness. The system comprises two synchronized applications: one for trainees in VR and one for instructors on desktop, enabling real-time feedback, scenario control, and remote assessment. The development process includes iterative design based on expert feedback, field testing in industrial environments, and integration of both technical and non-technical skill assessments. The solution aims to overcome limitations of traditional training by offering scalable, repeatable, and emotionally engaging simulations that improve retention, decision-making under pressure, and operational readiness. Preliminary trials demonstrate the feasibility and pedagogical potential of immersive VR for occupational health and safety training.