They'll even kill each other, if you're lucky.
There's some moment where they can't be reshocked immediately, and if there are a bunch of them, they tend to kill each other. When you're down to like 4-5 you can start picking them off. I generally try to run/shield away from them and leave them to their own devices lol.
When they aren't electrified charge and kill as quick as possible, try to interrupt their attack. If they are charged up, shield and move away as much as you can. Rinse and repeat. Good to have remedy capsules on you for sure.
Quicksilvers are usually fairly plain enemies. They're a Slime-type which makes them weak to Shadow damage and resistant to Pierce damage. In tier 1 and 2 the quicksilvers are just like plain lichens with faster movement speed. It is only when you Shock them that they become dangerous. When shocked they become invulnerable and pounce around, damaging other enemies, but to my memory they heal fellow quicksilvers. A quicksilver cannot Shock themselves outside of tier 3, so avoid using Shock vials and weapons with Shock-afflictions and you'll be good. If you do happen to Shock a quicksilver, back off with your shield up and pray they won't hit you. Their electrocuted form deals Elemental damage.
Hope this helps.
Keep your shield up, try to stay away from the area they're zooming around (I hear corners are nice but I've never dealt with quicksilvers in danger rooms). Dash in and do as much damage as possible when they're not electrified and dash out once they are. Also, try to kill the ones that aren't clustered with the others. Kill em one at a time and it should become easier.