She asks for ten minutes, she shall receive ten minutes. That also allows her to focus, since she trusts him enough for that.
Normally, that's a bit of a tactical blunder, assuming he's not preparing spells while talking. Talking takes time, and if you're buying time, don't interrupt your enemy while they're making a mistake. However, he's skilled enough with a weapon good enough to count on defeating him so he can handle the rest of the threats without worrying about him.
He also has a few other tricks up his sleeve, like protection enchantments. One of the benefits of a witch girlfriend.
A battle is not a place for personal doubts. If you have to stop and think, think about the battle.
It's not so much a question of whether double incantation exists, but whether you're skilled enough. Tinasha is.
"How much more do you want to make me suffer?"
Not at all, actually. He's irrelevant at this point.
Bunch of hooded figures, a knight, a well-dressed man, and a cute girl. Introductions are in order.