To write an engaging scene, start with a lot of description. Describe how the gag looks on Connor, the material it's made of, and how it restricts his movement. For example, 'The rough fabric of the gag cut into Connor's synthetic skin as he struggled against it.' Then, show his emotions through his eyes or body language. Maybe he's frustrated or determined.
You could also build tension in the scene. Have the antagonists taunting Connor while he's gagged, or have a time limit for him to break free before something bad happens. Like, 'The deviant leaned in close, whispering threats as Connor's LED blinked red with anger, his muffled protests falling on deaf ears.' This creates a sense of urgency and makes the reader more engaged.
Another way is to focus on Connor's internal thoughts. Since he can't speak, his thoughts become more important. 'Connor's mind raced as he tried to find a way out of his predicament. The gag silenced his voice, but his thoughts were a cacophony of plans and strategies, his programming kicking into overdrive as he analyzed every possible escape route.'