I get its fictional, I just like actions to have consequences I can wrap my mind around both in motive and execution.
Riley was a super soldier to be sure, and loved Buffy bunches, but I don't think it would be enough to override his nervous systems 'leash' (if it had been done correctly.) I think he just discovered his 'collar' was on kind of loose and slipped out of it.
Him knowing where to cut to remove it is a big stretch....Adam pointed out its location, but still....How did Riley know where to cut and dig to remove it?
There is much we don't know about Riley pre Buffy. Maybe Maggie was working on a similar control chip for HST's before she went the route of brain chip behavior modification? It seemed like Riley knew what he was doing, almost like he has saw it before, or something very close to it.
I don't think the chip was saddled on a nerve, maybe tethered to one and the linking cables broke when he dug it out. He couldn't pull out a thorax nerve without severely screwing himself up...least thats what I think.
I agree with pernilleborup as far as what we know for certain by what is told to us; it is a WTF moment. 🙂 There is more to the characters though that we don't know....its writers liberty! I love season 4 and am actually kind of fond of captain cardboard, so I've though up ways to give it all a pass.
I also agree with Hannah about why it was done...to show Riley's love for Buffy.
I imagine it was also done to show how wicked the initiative was in experimenting on it's living soldiers and removing it more from identification with the US government/army for viewers/fans of the patriotic nature. (Buffy vs the army might make for some sore fan base, but Buffy vs. a shadow group that experiments on their own people will certainly get a pass.)
As far as the love angle though... Angel could not break a curse for love of Buffy and Spike could not override his chip for love of killing....Love is powerful, but I don't think Riley's was powerful enough to override his chip.
Season 4 had a bit of a sci-fi bend and it's not coincidence Riley's chip was in his chest of all places....and could be removed with alittle battlefield surgery....least in my humble opinion
I've though long and hard about this, I credit that bit of heroism to a failed install by Professor Walsh, not Riley's love for Buff overriding the laws of biology.