Shoto remembers that one time that they were supposed to just sweep an area and not shove their face into something crazy. And yet he should've known that he and Izuku would've found something much more than that with both their knacks for getting in trouble. The resonating sound hits his ears and he frowns as he begins to realize it isn't just his own guess at what the sound is that's thudding waves through the very air around them.

The flutter in his chest isn't unnoticed, either, and his hand settles there very clearly uncertain of what's going on. He's not clear which it is, the sound resonating into his chest, or his chest resonating into the sound. His hand, again, grabs onto Midoriya's wrist and he pulls gently. He's unwilling to stop, but also, he pats his chest in time with the beating of that sound, trying to gesture that it's the same as his own. When he's done it, he points at Midoriya with a questioning look on his face.

They have no choice but to go on, of course, someone could be in trouble with how the people ran out of here. With how his heart is reacting. If he knew why that beating was happening and why the reverberations were under their feet, he might be able to just freeze the house section by section but without knowing who is there... He may hurt someone instead. Use of sound is a quirk in his world and even if it may not be someone from his world, he doesn't want to find out about them at the funeral he caused.