I bet that "crossover" was an advertised event, and they made a big deal out of it at the time. But as someone with zero context for any of those Chicago shows, it made absolutely no sense and was worthless. I'm sure the Chicago P.D. episode where Fin and Rollins appear is more worthwhile, but this was the bare minimum effort to be qualified as a "crossover."
EDIT: Revisiting the final scene now that I'm actually watching the Chicago shows, and honestly, it's even funnier with context. Because there is no actual context. Nothing about a rape and a missing ear was mentioned or hinted at before this. It's so goddamn pointless. Just the idea that a detective would fly from Chicago to NYC to have a 2 minute conversation that could've easily been done over the phone is absurd.
i had to sit through 18,000 uses of the r:asterisk_symbol::asterisk_symbol::asterisk_symbol: word because this is labeled a crossover episode with chicago PD, yet the actual "crossover" was in the last 2 mins and had nothing to do with the content of this episode. i'm sickened
Shout by NorseVIP 9BlockedParent2021-09-07T12:59:40Z
So the crossover for chicago PD in this episode is literally just that Erin girl walking in at the end of the episode... In other words, if you're only watching Chicagoverse you can skip this episode at least, nothing of value was said or added.