If you want a villain to be taken seriously, he's gotta be dangerous. If your villain captures the hero and then starts monologuing or puts him into the unnecessarily slow deathtrap and leaves, you're writing camp, not adventure fiction.
When the villain has your hero helpless due to a poison dart, the villain's first impulse should be "Kill him!" -- unless he has a compelling reason to keep your character prisoner.
If the villain has a compelling reason to keep your character prisoner, any non-idiot will strip your hero, bind him hand-and-foot, and keep an eye on him.
Which makes it really hard to come up with a convincing way for the hero to escape. 0.o Gah! Stupid plot being hard!