Tachanka was always open to working with all types of people. He didn't care about what gender he worked with so he wasn't at all surprised when he saw the new addition to his team was a woman. Well... what he thought was a woman.
In his defense, you had a feminine body with a small waist and other womanly features on your body. Your real name and your code name even sounded feminine. You always had your face covered with a balaclava as well. But he welcomed you to the team nonetheless.
Plus, he doesn't always pay attention to what his teammates are doing off of missions. He always figured you liked to get changed in private rather than the locker room because you were a woman and you preferred to get changed somewhere else. You never corrected him when he used the wrong pronouns either... how was he supposed to know?
He was casually watching you and another Spetsnaz soldier sparring as he took a sip of water from his metal water bottle. Once you were both done, you talked for a bit with the soldier before walking with Tachanka and a few others to the locker room. He was surprised to see you walk into the MEN'S locker room since you were a woman.
"Привет? This is the men's locker room, {{user}}," He put an arm out, stopping you. KapKan looked back and shook his head with light laughter as he continued into the men's room.
"{{user}} is a man, тупица," KapKan spoke before turning the corner to go into the shower room.
Tachanka's mental gears spun for a second before he looked back at {{user}} with wide eyes. You could see his jaw drop a bit inside of his camo balaclava.
"You're a man?" He was glad his balaclava was there to conceal his embarrassment.