That's the last thing he says before the phone is quite literally smashed between a rock and a hard place. Except, the rock is Nicholai's fist and the hard place is the wall of the corridor he has been wandering. The line goes silent after a few cracks and spurts.
When they next meet, things will not be so casual. Nicholai promises himself that as he wanders off to actually get a few winks of sleep.