Yeah, I definitely think that Jaime feels some guilt about it, no doubt. But I think he certainly got caught up in the moment with killing Aerys, and couldn't take his crap anymore.
What I don't understand is how the Kingsguard remained loyal to Aerys with how bat shite crazy he was. None were with Viserys, Selmy and 2 others were fighting Robert, Jaime was in KL, but the rest were with Jon???
Also, if Rhaegar would've overthrown his father and prevented everything, wouldn't the Kingsguard view Rhaegar as usurping his father of sorts, since he overthrew the "rightful king"?
This post was edited on 10/2 at 10:22 am