Eternal Vigilance when Pentexed?

If a locked vampire with Eternal Vigilance is Pentexed, can they still spend a blood to unlock, even if they can't block, as per the Pentex? Or, since the block attempt is obligatory, does it prevent the use of Eternal Vigilance?



Pentex(TM) Subversion
Unique master. Put this card on any ready minion. The minion with this card cannot take actions and cannot block actions. This card may be burned by any other minion as a action.
Master
Cost: 2 Pool

Eternal Vigilance
+1 stealth action. Requires an archbishop, priscus, cardinal or regent.
Put this card on this vampire. During an action, this Sabbat vampire can burn 1 blood to unlock and attempt to block. Burn this card if this vampire goes to torpor.
Action
Cost: 1 Blood

Cat_in_Exile wrote:

If a locked vampire with Eternal Vigilance is Pentexed, can they still spend a blood to unlock, even if they can't block, as per the Pentex? Or, since the block attempt is obligatory, does it prevent the use of Eternal Vigilance?

They can't block, so they can't use an effect that requires them to attempt to block.