Glorfindel doesn't tell Roland that elves ears are so sharp that he not only knows the direction, but could tell the man how many are in the group they were currently seeking out. He felt it would be rude at this point.

But he appreciates having Roland on his flank. The sewers were a little close for a bow, so he pulled out the tonfas that Cassie had given him. They would do the trick just nicely.

In the tales they would have come to a wider spot and faced off with their foes in a battle royale. Instead they came to...another section of sewer that happened to have rats in it. To give Roland some space to do his thing, Glorfindel leapt up, kicked off the side of the tunnel and landed on the other side of the rats, then started swinging both tonfa to take the rats out.