It was a joke, dude.
I kind of figured that out when you suggested Grayson and McCall together... But Taylor would have made a decent enough replacement for Kalmar, and a way to heap more pain, suffering and need for revenge on Carlyle. Oh well, missed opportunities...
IIRC, there were other subplots involving Lori Kalmar, Grayson Carlye, and the early members of his unit.
For example on one hand even as her feelings for Grayson were developing she was still sleeping with a fellow mechwarrior from the unit she was a member of when Grayson captured her.
Your thinking of the guy from Sigurd that was another captured pilot... She wasn't so much seeing him, as he was the last person from her homeworld and she needed company. The last time they were together was provoked by Grayson going to see his Trellwian girlfriend. She needed someone to talk to and felt very much alone. Before they even got out of bed, Duke Ricol landed, things went to pot and they all ended up trucking out to ThunderRift... Where he was killed.
By the second book, she was already being considered "The Captain's woman", which irritated her a bit as she hadn't worked out her feelings yet. And then add to that Grayson's liaison with Janice and she found the title almost ironic.
And her feelings toward Grayson were at war with her pathological fear of fire and Grayson capturing her by threatening her with an Inferno round.
The inferno round was part of it, but not all... She also suffered from a feeling of betrayal because when her Locust took an inferno round at Thunder Rift, she called his name and he didn't come in time to help. It is completely irrational, considering he was kilometers away, and she knew it (And let's set aside the fact that he actually did stop his dual on the tarmac to high tail it to the Rift to help her, something it doesn't appear he ever told her). But knowing something is irrational doesn't necessarily change how it affects us, and it haunted her until the author decided it didn't.