Like most Vampires, Laura got reduced into ashes and he placed them in the tomb, because having a Pot for ashes wouldn't be fitting for once a Christian man or Traditional vampire burial. Claudia was a side journey for Gabriel, he regrets everything that happened there. She was the first person to break his humanity on purpose if not counting the Brotherhood's conspiracy upon Gabriel. Why didn't she tell him about the vision? Some things could've been prevented and he already did a burial for Claudia in a lot of sorrow. First his wife got murdered just couple days ago and now he questions whether he was the one who killed Claudia or not and he probably blamed himself for the death of both Claudia and Black Knight. He buried her right after the battle, that's just grieving for sadness if you think about it. Laura in the other hand seemed like an evil child but Gabriel was probably surprised when she spared him after electrocuting him. Vampires are evil right? Why the mercy? That is pretty much a philosophy changer. After Marie goes into heaven, Claudia pops out, walking with a rhythm giving facial expressions like, "Gotcha, Biatch!" After his failed attempt to bring back Marie, Laura asks him for aid and explains now uncaring, stubborn Gabriel about the aftermath of destroyin the LoS, and she sympathizes and becomes personal when she is talking about Gabriel's current feelings. She even insults Gabriel when he decided not to care for the world and then there is a 300 year old vampire who's humanity was stripped a long time ago and now is an evil darkling talking about "gotta save the world". After that, Laura offers herself to her death so Gabriel can complete his mission... Laura was not hiding anything away from Gabriel unlike Claudia. Laura's role had greater significance than they did to Claudia. A lonely survivor with her Guardian as companion over an evil being that sacrifices herself so humanity can live to see another...