.....The other's apology did catch him a bit off guard in the moment, though no less appreciated for it. He hadn't meant for any of this to warrant or (and by god he hoped not) force an apology from him, though at the very least now he was sure he could leave behind any bitter feelings that may have tried to cling to him before. The words themselves he acknowledged with a short nod and a small smile, though Sato's next words had him pausing momentarily.
....."Anyways, you should probably make a copy of that key and put the original back. If staff start asking students about it and they find it on you, you'll be instantly busted."
.....Eyes moving down to the key he still held in his hand then, he quietly let the realization of the continuously real possibility that he could be caught wash over him, before a hand moved to the back of his head. Yeah, getting a copy would be the best course of action before they started suspecting too much and ended up catching the two of them up here, but would it be costly? ...Nah, I'm sure there's a cheap place somewhere, it can't be that bad. I bet Umeko would know one, I'll have to ask her tonight.
.....His attention finally returned to Sato once he spoke again, gaze snapping back up before looking over to where he seemed to be talking about: the building keeping cover over the stairwell.
....."Up there?" He echoed, staring up at the top for some time as he let his thoughts take over once more. A quick glance around the rest of the surrounding area proved that it was mostly dirty, and with the very old and not very reliable state of the railings, it would probably be best not to be anywhere near it, no matter how much Hiroyuki tried to laugh off the idea of the potential of falling to their deaths from the edge. A single misstep and they'd be a goner. No way could he explain that to his mom, especially if he was the one who ended up dead in the first place.
.....Up on the top of the miniature building, though, would likely be cleaner than any of the area before them was looking, and even though the risk of falling remained, the height from that top to the roof's was much smaller and would likely only result in some scrapes and bruises at best, or a sprain at worst. Or so he hoped.
.....A new smile he flashed in his classmate's direction then, excitement building once more. So not only was he okay enough with this whole thing to seemingly not be on the way to report him, he was totally on board. "Nice eye, Sato-kun! That'll be perfect."
.....Hiroyuki could definitely count this endeavor as an absolute success.