The 'training mission' trope is as old as the Red Army and it's bullshit.
They pulled the same shit in 1956 when they got captured by the Hungarians and in 1968 when they invaded Czechoslovakia: 'We were told it was a training mission'. This is straight-up a survival tactic for the prisoners. They're playing dumb and acting innocent. It's impossible not to know by now where, what and why you are doing in a foreign country, in a fucking military convoy.
how could any of them possibly still think this is a training mission? they're in a different country shooting actual people and buildings, and actual people are shooting back at them.
Wow! These scenario role players are incredible. I'm getting so much training value! They fall down, cry, bleed out, and die just like somebody would in real life!
Initiation of an actual radioactive disaster near your own border on purpose…