You have to explain to your siblings that there are trolls and awful beings on the other side of that microphone. Tell them, "what they say isn't true, they're just cursed thralls". Explain that terrible things can happen and they themselves can release their anger by letting out a loud "-blam!-!". It will relieve them from bottling up the curse set on them by those awful cursed thrall. Or mute the mics from the speakers and use no mic. Or use the mic for your bro. Or just notify the fireteam that you can't talk, but know what to do and that you have to turn the mic off, so you won't get booted. But it looks like your bro was going to get booted regardless.. that's just -blam!-ed up. Damned those cursed thrall.