Headcanon
The events leading up to David’s death and Eve’s kidnapping are unclear to Selene (as well as the audience), and neither David nor Eve ever seem willing to expand on the details surrounding it. The following sequence of events describe the occurrence as @hybridiism and I have interpreted it.
Selene insists that David take Eve and protect her as best he can while she fights off Quint in his über lycan form. Although both are aware that David is mortally wounded and will likely die within the hour, David agrees and takes the girl under his arm. He leads her farther into the Coven’s chambers, where there are fewest entrances and a greater chance of survival.
****It should be noted that David immediately begins feel to the effects of the Lycan venom, as we see him limping down the hall with Eve in tow. He posture appears to be hunched over and babying his wounded side; this more than suggests that the effects are immediate---a direct contrast to the way Eve managed to survive over two hours, despite her having the exact same wound.
David, Eve, and what remains of Thomas’s coven fight off Lycans that attempt to breach the inner chambers. Selene is subsequently defeated and knocked unconscious. Quint in his über lycan form continues through the Coven, dispatching stragglers as they attempt to fight or flee.
As Quint breaches the inner sanctum, David charges headfirst into direct conflict with the giant lycan. He sustains increasingly severe injuries as Quint bats him about for several long moments; such injuries include several broken ribs and a punctured lung. The assault ends with David broken and pinned beneath one of Quint’s paws as the Lycan prepares to tear David’s throat out. The only thing that stops Quint from following through is Thomas’s intervention. It is here, with a knife at Eve’s throat, that the exchange is made: Thomas’s son and the rest of the coven undefiled for the hybrid girl in return. Quint transforms back into his human form, bloodied and black-eyed, and he agrees. He leaves David where he lays and collects Eve. He drags her away by the hair just as Selene comes to.
When Selene finds David and Thomas, David is bleeding internally, struggling for breath, and suffering as the venom circulates a dangerous fever. All he manages is a single phrase: “They took her.”
David dies feeling a failure to Selene as well as being responsible for the deaths of his people and a disappointment to his father.













