it's in my nature {Tangerine | Bullet Train}

Tangerine doesn't say that he's still feeling a smidge of guilt on the off chance he thinks about that civilian he inadvertently got killed back in New York, because he doesn't feel guilt. Maybe he feels a bit responsible; she was targetted because he'd used her for information, among other things, and gotten noticeably close to her, and perhaps he'd chosen her simply for her charmingly ironic name - Clementine - much to Lemon's chagrin, but in the end it was a secure sense of self preservation that kept Tangerine from putting himself in danger to save her, and so he's not going to feel guilty. It's a facet of his work. Collateral damage.
However whatever guilt he may or may not have been feeling evaporates less than an hour after he boards the Bullet Train bound for Morioka, when upon trying to deal with an already stressful rescue attempt for the scariest motherfucker in Japan, he comes face to face with Clementine, clearly not as shot in the head as their last encounter implied. He's not the only one surprised.
The absolute last person disgraced mercenary, 'The Scorpion', expected to see was the hitman she had been hired to get close to for an intelligence gathering sting several months ago on the other side of the world. She even faked her own death so there was no chance he'd be able to consider following up with her, that bow was meant to be tied and in the past! Now here he was, on the same goddamn train as her client, and he's effectively babysitting the bastard who was responsible for disgracing her in the first place!
This was meant to be an easy job, watch over The Prince until the train arrived at Morioka, but unlike her boss's daughter, The Scorpion never had any such luck.