"Frothing!" he declared with half a thought in response to Bethen's exasperated (and likely rhetorical) question, giving the disgusting thing a final kick to the abdomen just before she grabbed him. Several cubic feet of solid spider failed to shatter as its legs had; disappointing, but to be expected. He really didn't need encouragement to run for it, but he let Bethen haul him along anyway, the scratching noises of spider feet echoing through the chamber at the forefront of his thoughts.
When she stopped unexpectedly he became confused, even a little irritated, but he slowed down with her anyway- in part because she still had a surprisingly firm grip on his arm and he'd have gone toppling forward if he didn't. Why stop NOW? He was about to say something snippy (Just how smart do you think these giant bugs are exactly?) but caught himself when she withdrew her hand and retreated abruptly with all the horror of someone who has just realized they've been standing under a wasp's nest. Maker, was she blushing? He noticed then, as she started to speak sternly, how heavily she was breathing. It hadn't even occurred to Constans that she might not be able to sprint as far or as fast as him. He wasn't even near out of breath after covering that last tunnel, but should he really be surprised? Few of the other mages cared to stay in shape the way he did; sixteen years old and he still ran everywhere, indoors. A little exasperated by this realization, he still found he felt nagging little bit of sympathy for Bethen because of it, and abandoned the idea of demanding that they keep going. For all he knew they really could be flanked up ahead, and he certainly wouldn't leave her behind if she couldn't keep up with him.
Given that he was surreptitiously watching Bethen's chest for a good chunk of her speech, for surprisingly innocent reasons, he blinked at her when she offered him her staff and took it without thinking. He had to replay what she'd said over in his mind, subtracting his wandering thoughts from the equation.
"Yes, let's not set the place on fire. If we crawled out of here alive, Alden would just kill us anyway." He stepped cleanly out of Bethen's way and brandished the staff in the direction the worst of the awful spider swarm-sounds seemed to be coming from, down the path they had just put to their backs. He tried not to let on how shaken he actually was at the moment, his face settling on a serious expression for the first time since Bethen spoke to him, while he cursed silently and hoped he hadn't just seen something (or many somethings) moving lighting-fast toward them across the shadowed concealment of the the tunnel's rough ceiling.
"Theoretically," Constans murmured, the clack-clack growing louder, "What would we do if they came from ab-"
He glanced up to punctuate his surmise just in time to see a tangle of legs and fangs dropping down upon them. Tongue frozen to the roof of his mouth, he thrust Bethen's staff into the air between himself and the airborn attackers without even uttering a sound, a percussive ripple bursting through the air around him and shuddering against the stone walls.
Plop plop plop, three hound-sized spiders stunned by the mental blast came raining down upon the pair of students. Constans brought the end of the staff down upon one with a growl, crushing its carapace before it could recover as yet more of the creatures bore down on them in the indistinct darkness.