Naturally, this whiny idiot does not get spitted on a sword, like he deserves. At least in that circumstance, he was defended by his compatriots. Later, however, he's put at the mercy of his enemies who...take mercy on him. For some reason. Even James Bond didn't have villains like this.
Now, this isn't a bad novel, in fact it's this isn't even a first novel, this author has been published before and has a multi-book contract. So they're doing something right. But they're also doing something wrong.
They're not letting their heroes save themselves.
I like heroes who are active, who get into trouble and find a way to fight or think their way out of it. I respect that. I respect them.
Its great to have a huge, powerful enemy. That's cool. If you show the enemy being so powerful they can manhandle the main characters, that build tension. When the main character's attack and fail, that raises the tension even more. When some guy who's had two scenes in the past four hundred pages suddenly flies in, out of nowhere, to save your main character...that kills all the tension.
Take Star Wars, which on the surface has this kind of 'out of nowhere' crisis resolution. Luke is attacking the Death Star. Darth Vader is blowing the crap out of every X-wing that gets into the trench and he is terrible, unstoppable. Luke can't beat him. What happens? Luke doesn't give up, he keeps trying, he uses the Force to delay Vader's attempt at a lock-on. Then, just as Vader has Luke dead to rights, boom, in flies Han Solo to save the day. On the surface, this seems to be the exact thing I've been complaining about. But it's not. Luke is not the only main character in Star Wars. Han Solo is as well. Han Solo saves Luke and redeems himself in doing so. That works. Having one of the barflies from Mos Eisley suddenly fly in and save Luke does not work. As cool as the devil-guy may have been, he hasn't been in the movie enough. He isn't a main character.
If you've made your villain too strong, then you have a plot problem. Give them a flaw. Go back and lay the groundwork for how the main character can win. That's what revisions are for.
It doesn't have to be that deus ex machina to still be unsatisfying. If your main character is sitting around waiting for their romantic partner, sidekick or familiar to come rescue them, that's just as bad for me.
Your main character needs to drive the action and they need to be constantly trying. If your plot has the main character winning and surviving (and I highly recommend that) make sure they are the ones who are cutting the heads off, unlocking the vault door, defusing the time bomb. That gets my blood pumping, makes me want to cheer. Make your readers cheer.