Getting his foot on the first step wasn't that hard, it was pushing off, putting your weight on that foot before the other could reach not even another step but the same one that had his jaws clenched. He tried not to lean quite as heavily on Percy as usual, supporting himself on the rail, but three steps later he had to stop and rest for a moment, his forehead damp with sweat and his insides protesting.
He did want to make it though, or at least manage a few more steps if only because he didn't want to give Percy another reason to worry, to want to be too careful, to back out. He was quite sure Percy could never hurt him no matter what they did. He was too cautious by nature. He'd insist on taking it slow.
Not that Cass minded that, especially not since he slowly - far too slowly - forced himself to two more steps before giving up the effort. He'd have no energy left for anything but sleeping if he took another step on his own. Actually, as much as he hated to admit it, he already knew he'd need to lie down and rest before having the energy for anything at all once they got up.
'I think this is my limit for now,' he breathed, trying to keep his breath steady even as his heart hammered with the effort. Fuck he hated this.