Mr. Gu left the containment area with fear in his mind. There was a reason he was shocked when his swords disappeared.
The containment cells were all built with a mana-inhibiting glass that would reduce the impact of mana usage against it. But a second measure would also restrain their occupants even more.
Under each cell was a machine that siphoned away mana from its occupant constantly, to the point that it should negate the usage of their power entirely.
But Alexander had ignored those and suppressed him and Ms. Deveille from inside his cell. This effectively meant that the cell wasn't even restraining him.
He was only inside it to reassure them.
This attested to his current state of mind. But what if that changed?
What if he decided he had wasted enough time here? What if he lost control of his powers?
Mr. Gu didn't trust him to be in complete control. Not after what Jack had told him when they came back.