Boom took a moment to glance at both of the items for a moment, while No Point was disposing of the body. It was good that he was taking care of that. It would've brought unwanted attention for sure, if they noticed it.

 He knew he would have to blow on one of the two. Hopefully he would choose the correct one. And of course, when his kin showed up, he hoped they wouldn't proceed to immediately go after him. After all, Boom knew he was, not particularly liked around these parts. 

It was the reason he joined the caravan after all. He made far too many enemies in his time in his old stomping-ground at the Kokiri Sinkhole. This, Boom was sure this would only end badly. For him at least, he knew that whichever horn he used, Boom probably would not have a good time from the result. Boom carefully held each item up for a moment, as he took another glance at it. 

"Hnnn, which one. Which one!" He stared at the horn, the source of the big-loud greeting. Then he stared at the conch, the source of the quiet-small greeting. As Boom figured out the decision, it was around the moment No-Point returned.

He held out the horn as he blew upon it. As he completed his use of the horn, he immediately turned to glance at the fellow caravan members. "Boom, not likes greetingses. Hideboom." He spoke with a sense of urgency, as this was a matter of urgency. 

Boom simply he hoped that the correct response would occur. Namely one that didn't involve them all his Kokiri brethren going after him and trying to ruin his survival.