Idk I don't think Grayson done anything bad here any rational or sane person would have run away, you seem to forget Grayson is a parachute hire and an actual civilian. Now before you say he is in Firefighters so he should do his work, everyone there knows how risky it is to send Grayson inside who has no prior training but they did? So it's their fault not Grayson.
You also forget a lot of normal people things, I think most people would like prefer their own life than other people I am not saying anything but that's the truth as civilian anyone would have chosen themselves and Grayson did so it's like that, like see we expect people to be Mary Sue type of kindness but most people will never be like that and be selfish and that's the same thing applies here. Then as for Grayson leaving the novel explained better like he was planning to drag Dane back by force but dane doesn't listen even after Grayson warnings to turn back because the house was breaking apart and collapsing, even everyone told to turn back but Dane didn't listen, but Dane told Grayson to leave and stop being liability and ran away leaving Grayson alone, so Grayson done what he had to do he stepped out

Grayson is trully a bad person. Like deadass he’s so fkn fake any suffering he goes through is 100% deserved. Dane better cheat on his ass 10 times over