She's not better than that. It felt out of character for Kurt, but definitely not out of place for her. She is the same woman that survived Genosha when 16 million mutants were massacred around her to the point that it created PTSD and nearly drove her insane. There was survivors guilt that she carried bc she couldnt save her people and her father Magneto was dead
FF a few years to Krakoa, Magneto is once again dead and there is another massacre at the HFG. Lorna left early so she wasnt around to help save anyone nad prevent that from happening. Her best friend Jean, died that night as well as Bobby whom was another longtime close friend. When thousands of mutants went to the gates and were MIA, they were presumed dead. And this was all bc of Orchis, an anti-mutant organization thats made it their mission to destroy mutantkind. Like they cant live openly on Earth without fear of being openly killed by the Stark sentinel or deported to Arakko where they will likely get slaughtered once orchis has purged Earth. I really think you should consider all this context when it comes to judging Lorna's actions. This is not only personal for her but she's fighting for the few mutants that are left
The 16 Million dead on Genosha very much inform her actions