Marla glanced at her watch. Half past four. She'd been in the subway since morning, doing nothing in particular—just watching trains come and go, people getting on and off. A typical commuting scene.
My first impulse was just to write getting instead of get. But after reading the sentence again I said: wait I wrote come and go shouldn't I write get instead? But after replacing it with get something seemed off.
So I'm a bit confused, should I use get or getting?