Indoraptor Drop stone into the hole

I slipped through the cracked service door and ventured outside. The indoor ceiling was gone; damp morning air hit my snout. I stalked across the gravel path toward a cast-iron drain grate set into the stone pavers. A smooth white pebble rested on the rim. A low rasp rattled in my throat. I lowered my stance, hooked the pebble with a curved foreclaw, and nudged it over the iron slot. It clattered against the metal bars, tumbled through the dark gap, and struck standing water below with a crisp, echoing plop. I froze, head tilted over the grate, listening to the hollow drip. Ground tested. Nothing came back up.