Elros and Elrond are guarded, the precious hostages/fosterlings of some of the most lethal elves in Arda. But Beleriand is not safe, not here, on the edge of the knife. Far younger than Maglor would like, far sooner that Maedhros deems is safe to allow it, they are trained to the blade and sent to the front lines, or as near it as makes no difference.

They are guarded, yes.

It doesn't mean they don't get injured.

"How many fingers am I holding up?"