Just like it says. We have a Sorcerer who is under the Restrained condition, which says that attacks made by the Sorcerer are made with disadvantage. But the Sorcerer has the Subtle Spell metamagic option and thus would not need to speak or move to cast spells.
Can a restrained Sorcerer use the Subtle Spell metamagic to cast attack spells without disadvantage? Whichever way the answer goes, what’s the in-game rationale?