The hand holding Adrienne's tightened almost imperceptibly.

Spock's expression tightened ever so imperceptibly.

The barrier was tightening imperceptibly as he approached.

His arms tightened imperceptibly, effectively trapping her.

Her thin lips tightened almost imperceptibly.

His jaw tightened almost imperceptibly, and he started forward with Narcissus, resuming the walking he had stopped to smile sweetly at her.

The finger on his trigger tightened imperceptibly.

'You can let me go now,' Jenna said stiffly, reminding him that he was still holding her in arms that were beginning to tighten almost imperceptibly.

The wrinkles at the corners of his eyes tightened almost imperceptibly.

His fingers tightened almost imperceptibly, although his expression remained bland.