1. Engine compartment fire extinguisher(s) are an option on the EC-135.
2. FAR 27.861 stipulates that, each part of the structure, controls, rotor mechanism, and other parts essential to a controlled landing that would be affected by powerplant fires must be fireproof or protected so they can perform their essential functions for at least 5 minutes under any foreseeable powerplant fire conditions.
An un-contained failure of an engine and the resulting damage to the firewall and other fire protection could easily nullify the above.