Too many changes in one go at a crucial time

[VestasBoro]

He didn't go missing, he'd literally just put in a cross by their corner flag.

They counter attacked immediately from that cross and he's not Usain Bolt, harsh to expect him to get back in time from that position.
Other players should have picked Rusyn up.

Tactically then, when the LB goes forward someone covers the LB spot and becomes the LB until he gets back, that player went missing.