Check this one out: https://itch.io/jam/no-video-jam/rate/736066
This is from a similar jam that I organized during lockdown. The submission is a stealth game that the community found very successful. You made something that I would have made back then. (Now I make abstract things with synths on purpose.) The sound in Unwanted Passengers, on the other hand, is very diegetic. So that’s a good instinct to try to consider the physicality of it. If you want to stick with the synths, then you might just tighten the release to get them snappier, and then trigger them whenever the guard steps. It will sound pretty cool no matter what.