can someone explain the symbolic meaning behind the last image of ch23...?

They're trapped in their roles as bonded mates. Granted, bond surgery removal does exists, but at great risks to the omega (high mortality & side effects). From what I can tell is that in the past Ian had stayed away from omegas (both in his social as well as in his sex life). So idk the reason behind that. A good strong possibility is that he didn't wanted to be mate bonded. Another reason is to not have kids. So, that choice was taken away from him. So he feels trapped. The irony is he doesn't HAVE to take Noah as his mate though....

But that means Noah would have to break the bond?!?

Plotholes.