Or should he prevent the chief vampire from gaining hold of the book and risk never seeing Zack again?
Leaving aside Ephs qualms about Quinlans vampiric side, theres no question which is the more appealing choice.
Is one taste of the Masters blood enough to sway a young boys loyalties?

Credit: Michael Gibson/FX
Even if it means turning to Setrakian for help.
He goes on to say any successful effort must take place during an occultation.
According to Fet, the next eclipse in New York City isnt scheduled until April 8, 2024.

Plenty of time for the Master to subjugate the human population.
He suggests Palmer should exert his influence over Justine Feraldo to encourage more visitors to submit to medical examinations.
Should Palmer find Setrakian and retrieve the Lumen, then perhaps the Master will deign to consider Palmers needs.
Referring to Palmers decades-earlier betrayal, Setrakian refuses.
I have the Lumen and I have the White what do you have?
While Palmer thirsts for the stuff, Zack comes by his first dose unwillingly.
He flees, pursued by Kelly, and is soon in the midst of a severe asthma attack.
She hovers over him, stinger partially extended as the boy struggles to draw breath.
He swallows, and the attack subsides.
Thats when he makes his pitch for a different plan.
The Lumen will bring the Master out of hiding.
When he comes for it, Ill kill him, Quinlan says.
It will be interesting to see how this unlikely partnership plays out.
There might be some other partnerships on the horizon soon, too.
Heres betting well see her back in the fold next week.