How do I disable Siri pop-ups on my school MacBook Air?

I'm using my school Macbook and recently the admin of this Mac turned off Siri, which is fine, but I had 'Listen for Siri' on and whenever I'm just doing my work or drawing, this pop-up is saying I don't have permission to use Siri. I'm not even saying her name but I think that it's just the background noises making it activate.

I've also went to the admin to ask him to turn off Siri completly but he didn't do anything besides making my keyboard language to US.

All I need is for somebody to know how to turn this off so I don't have to see this pop-up every 10 seconds or so.

[Re-Titled by Moderator]