"That's fine." She calls back as she steps onto the train, finally turning back to face him now that she's there. She has one hand settled onto the support beam where she's standing. A few moments later the train is announcing 'please stand clear of the closing doors'.

"I'll buy you lunch later." She offers it in her usual emotionless tone, with no indication of what her thoughts are in this moment.

Then the train doors close, and she's gone.