personnel of compartment 2 were poisoned as a result of the incorrect actions of the commander of this compartment , who connected the sds to the medium-pressure air system according to the back-up procedure , and then the submarine 's command , which disconnected the high- and medium-pressure mains without warning the personnel of compartment 2 of this ; 2 . personnel in compartment 5 were poisoned because the commander of this compartment failed to monitor operation of the sds system , which was receiving air from the damaged cofferdam no. 1 of the high-pressure air main , and the incorrect actions of the attack center , on the instructions of which air was cut off to the medium- pressure air system without the personnel of the compartments being notified .