Continuity mistake: After Selene has killed Viktor she approaches Michael from behind. We see him turning his head. When it cuts he turns his head again. (01:46:10)
Other mistake: When Selene's car plunges into the Danube, her car hit the bottom of the river on it's side (the passenger's side). When the camera closes up to the window of the car, you can see water flowing in from the roof of the car (as a result from the holes created by Lucian). It should flow (or at least accumulate) towards Michael's direction because of gravity but it did not. (00:29:45)
Continuity mistake: When Michael was captured and hung up, and meets Lucian face to face, Lucian injects blood into him and the syringe has an air bubble in it. In the next shot, the bubble has gone and the syringe is entirely filled with blood when being injected into Michael. (01:23:00)
Continuity mistake: In the last fighting scene between Victor and Michael, Victor's face gets scratched and it starts bleeding. In the next shot, his face is completely cleared of his scratches. And in the next, the scratches appear again.
Revealing mistake: At the end of the film when Viktor and Michael are fighting you can see Viktor pulling his punches. (01:47:35)
Answer: Lucian does not die instantly after being shot by the silver nitrate bullet. This also is after he injects himself with Michael's blood. With that said there was a scene where Raze comes back with Amelia's blood (she is an elder). He checks on Lucian while dropping the bag of blood right mext to Lucian. I am absolutely certain he noticed this bag, injected himself with elder blood before he crawled out to stab craven in the leg. Lucian will be back and this was part of the story. When he comes back, they will show the audience in a flashback of Lucian injecting himself.