Yashin, based on domestic revenge, decided to kill

Yashin, based on domestic revenge, decided to kill

Yashin, based on domestic revenge, decided to kill Alalykin. He aimed at it from a loaded hunting rifle and fired. However, at that moment he stumbled, and the bullet hit Shabusov, who at that time went out onto the balcony.
What mistake is contained in the actions of Yashin and what is its significance for qualification?

Additional information:

After payment you will be available a link to the solution of this problem in the file of MS Word. It should be noted that the problem solutions put up for sale were successfully handed over in the period 2009-2019 and could be outdated. However, the general algorithm will always remain true.