Thankfully, Glorfindel does. Yes, he swore to find and protect the twins, and he is, but there are older oaths at play here, and he cannot (will not) forget them.

Thus, it is a conscious decision to turn his back on the latest wave of orcs so he can draw one of his knives and send it and send it flying across the open space in a shining arc. It sinks into the threatening orc's eye to the hilt, but he has his hand on his other knife, just in case. He waits to see the orc drop before turning back to his own fight, almost entirely too late. He catches a black orc blade along his ribs, the armor turning most of the force but eliciting a pained grunt before Glorfindel can return the favor and send the creature's head rolling in a different direction than its body.