  Manoeuvring in the presence of emergency vehicles is still a major issue for
vehicle autonomy systems. Most studies that address this topic are based on
rule-based methods, which cannot cover all possible scenarios that can take
place in autonomous traffic. Multi-Agent Proximal Policy Optimisation (MAPPO)
has recently emerged as a powerful method for autonomous systems because it
allows for training in thousands of different situations. In this study, we
present an approach based on MAPPO to guarantee the safe and efficient
manoeuvring of autonomous vehicles in the presence of an emergency vehicle. We
introduce a risk metric that summarises the potential risk of collision in a
single index. The proposed method generates cooperative policies allowing the
emergency vehicle to go at $15 \%$ higher average speed while maintaining high
safety distances. Moreover, we explore the trade-off between safety and traffic
efficiency and assess the performance in a competitive scenario.
