Oy. I hope she learns from this experience. It may be worth taking her out for coffee and talking to her about puzzles.
Keep in mind, though, that this mysterious benefactor is an insane villain a la the Joker. If she's planning on having him be a long-time character, she needs to realize that the players will hate and resent him and regard it as a failure every time they buckle under his desires; unless she herself is a sadist, this vampire is a villain who should be opposable without breaking the campaign.
Last night we finished a mini-campaign full of deadly puzzles. At the end, the entity who created the puzzles congratulated us on getting through them and passing her test and showing our dedication. We were all, "Hold up. First off, you killed one of our friends to
test us? What the *@#$?! is wrong with you? Second off, if you want to test someone's dedication, maybe you shouldn't
lock them in your complex. We woulda left this hellhole as soon as we could've if you had let us." One of the characters swore that after the entity died, he'd spread tales of her viciousness and evil throughout the land, forever tainting her memory. I don't think the DM was quite prepared for that reaction

.
Puzzles are tricky: what's obvious to one person is completely non-obvious to another. The guidelines given in this thread are very good:
-Puzzles should never be bottlenecks preventing forward progress.
-Puzzles should have clear guidelines, such that when you solve them, you
know you've solved them.
-Puzzles should never kill a PC.
-Puzzles should either be closely integrated with the storyline, or they should be self-consciously goofy in a lighthearted game.
Daniel