Excellent, colleague. I'm glad that you have recieved Level 2 access. At last you will find out what goes on in our laboratory.-Chief of Lab X-18, Piotr Ilyitch Kalugin
As the head of the X-18 laboratory, Kalugin was fully aware of what was going on in the most secret areas of the facility and was a member of The Group. He was responsible for granting access to the more secret parts of the facility to lower ranking researchers.
For one reason or another, Kalugin, along with the entire staff of X-18, was killed when the mutant specimens contained inside X-18 broke free and killed everyone inside.
Shadow of Chernobyl
Kalugin is mentioned in two PDA entries in X-18. His corpse can be found in a room inside of Lab X-18, near the entrance where two Snorks will ambush the player. After searching his corpse, the player will obtain information about second combination number, that can unlock the last code locked door to the control room; despite it not being locked in the first place. The door code he is holding is: 1243.
Kalugin's corpse hold the following: