Grivtsov, working as a collector

Grivtsov, working as a collector of the Norilsk branch of the State Bank, in the evening, along with collector Shalaev on a Volga car, he collected money from retail outlets. At 21 hours 30 minutes they drove up for money to the Agat store. Grivtsov went to the store, and Shalaev with the driver remained in the car to guard the collected money in a large amount. Skrylev, Sinichkin, Chernov approached the car. Not knowing that the car was busy with the job, they began to ask the driver to give them a lift. Having been refused, Chernov decided to talk with Shalaev, mistaking him for a passenger. Sinichkin opened the door, Shalaev tried to close it by hitting Sinichkin in the arm with his foot. Sinichkin in response grabbed Shalaev by the leg. Shalaev, having decided that these persons attacked him with the purpose of robbery, shot without warning through the glass of the back door and wounded Chernov. Hearing the shot, Grivtsov ran out into the street and, without understanding the situation, there was no one near the car, shot at Karamyshev, who was passing by, mistaking him for one of the attackers, which caused him serious bodily harm.
Solve this problem in terms of the legitimacy of the necessary defense. Designate the limits of criminal liability of Grivtsov and Shalaev.