User blog comment:DiegoAnime3000/Yang vs Tifa Death Battle/@comment-25405817-20151021025617/@comment-24994749-20151021035417

Yeah, Laura had an "What have I done?" moment, some moments after OAG died, but she didn't get the full fledged reaction until more than 24hs later. Heck, when they just get into the library with the camera, she was almost cool, enough to comfort LF. And she had way more fuel to explode than RWBY did in Breach.

When Laura killed OAG, she had just seen Danny die in her arms.

RWBY has way more factors on to delay their reaction, including, in adittion to what I already mentioned in my previous comment, that they didn't directly inflict the WF members the fatal blown.