pockethealing:

Little theory here! I could be wrong though, so keep that in mind. I think that Gabriel may have wanted the Soldier Enhancement Program for Blackwatch/Overwatch. It would 100% help them. So, he went to Moira- the Blackwatch support. We already know Moira is shady. She isn’t a good guy here, no matter which way you look at it.

Her peers didn’t like her ethical shortcomings, which leads us to be that she may have experimented on omnics and humans and used possibly harmful methods. For example, she could have unwillingly tested on people and omnics (especially omnics since they are considered to be ‘below’ by some people) and used possibly illegal drugs and shit like that. 

Anyway, I think Gabe possibly went to her and asked her to help reverse engineer the SEP so he could get ahold of it and use it on other agents. If not that, maybe he wanted to remove it’s hold on him. Moira could have done just that- but did a bit extra without Gabe’s consent.

You see here that she is eager, while he is obviously confused. This is just before he starts to get his little reaper wisps. He isn’t happy. This isn’t what he wanted. If it was an accident, wouldn’t Moira be more concerned? 

Further more, Moira is in the same costume as Mercy but her “halo” is broken and she has horns which could represent being evil. Also, as you know Moira is Irish. In Irish folklore, they have a feminine creature called a Banshee that can predict and bring death. They typically look like this.

If you notice, the hand Moira has on Gabe’s shoulder sort of looks like this. Seeing she is Irish and has made Gabe into Reaper, I think this whole banshee ties help solidify what she did was on purpose and intended. 

Now, as for Mercy and Gabe’s hostility towards her? Maybe she had promised to help and tried to, but only made things worse. It isn’t exactly clear but he is hostile towards her and puts her to blame for some of it. It is confirmed though from the video that Moira did do this to Gabe, and this entire post is just a back up to solidify it and try to give a motive. 

credit to @still-boldly-going @owr-tips-and-tricks and @attamo for help and theory discussion!