I really really REALLY love it when the seme comes and saves the uke from danger but in this case the danger is the uke. For instance, the uke is losing hope on life little by little and is going down a self destructive path that could eventually kill him, so the seme steps in and stops him. Other examples could be:

 -The uke lives with an abusive family and puts up with it so the seme rescues him from the abuse.   
 -Or the uke is suicidal so the seme stops him.   
 -The uke is being self destructive through drugs or alcohol so the seme tries to help him.   
 -The uke has some strong power in him that could make him go insane so the seme tries to save him.  
 -The uke gets manipulated or brainwashed by someone into doing something life threatening so the seme stops him.

Some manga like this is Yellow, Cut, Crimson Spell, Wild Adapter, Switch, Ilegenes, and Wild Fangs.

I consider Wild Adapter, Ilgenes, and Switch shounen-ai manga.

Stuff like that. I love it when the seme saves the day! n.n Thank you greatly for all those who answer!! 😀

BrandNewWings

Acid Town
Brother x Brother
Hohoemi no Nichijou - Hinata
Love Mode

Under Grand Hotel - Kiss & Kill the uke is suicidal so the seme stops him

Zankoku na Kami ga Shihai suru kind of matches this idea, but be warned that the series is long, intense, and pretty dark. Also the art style is old (but despite that Hagio Moto's art is really cool/interesting imo).

Also I don't 100% remember which one is uke/seme, but I think Ano Hi no Kimi wo Dakishimeta nara fits too.

wisdomofmanga.tumblr.com

It's pretty short but Tsuki ni Hoero ch 4 has an uke with suicidal tendencies