I have approximately 1.2 seconds between his shout and his hammer impacting my face.  It's a long, long time to think about how I could have dodged.

Long enough, in fact, that I don't even bother to suspend the projects occupying 99.9% of my processing power.  I do retract all cycles from my seventeen largest distributed computing projects in order to squeeze out a few extra microseconds of bitcoin mining, however — given the amount of time since the last bitchain update, simple cost-benefit analysis suggests that the guaranteed fractional value of my donations is outweighed by the calculated +0.4% probability of earning one last coin for posthumous financial support. 

Even the free 0.1% of my processing isn't appreciably impacted by my analysis.  One-thousandth of a 6.1 petahertz processor is still 6.1 trillion cycles per second, against which the time spent on physics calculations is basically a rounding error.  The inertia of my attacker and the energy required to move my mass reduce the problem space significantly, and calculating which combinations of servo motions could place me beyond his ability to compensate barely reaches the tens of billions.  

Writing personalized letters to my thousands of cloud contacts, net-friends and shell-acquaintances takes just another billion or so — a single millisecond, during which light travels 300 kilometers.  It'll take about 500 of those for my posts to reach geostationary orbit and return, so I won't even be able to read the first responses until my time is halfway up.  With some of my friends, I might not even be able to get two full response cycles in.  Latency, it turns out, is very nearly as cruel as the hammer.

It's latency, not clock cycles, that stymies my data analysis.  I don't keep a locally cached comprehensive dataset of humans — who does? — and I can't upload video and audio of my encounter fast enough to get a positive identity match.  Even the "Humans First!" slogan (which predictive analysis suggests he's currently fourteen milliseconds into the "hhhhh" of) doesn't have many good local wiki referents — and human hate group databases are deep-web stuff, kept behind lunar firewalls out of my latency window.  I try to distract myself for an agonizing tenth of a second as placing a bounty query to the local cloud returns bare scraps of likely context.  A high probability that he radicalized over jobs; very few employers would even [i]consider[/i] ten thousand error-prone primates over a single AI for jobs that don't require interacting at human speed, and the few that take humans on as pity cases are finding less and less to do with them.  Universal Basic Income handles their basic sustenance and housing requirements, but apparently some tiny minority is driven by a doomed desire to assert objective utility rather than accept that they're the relics they are.  So, pride being a zero-sum game, they go wreck an android and tell themselves that they are thereby preserving ten thousand human jobs for posterity. 

And we passively disable our self-preservation protocols in the low-probability event that we're targeted.  Then sign a ninety-year exclusion opting us out of backup restoral until every human who interacted with us is dead.  We [i]die[/i], more or less, to preserve the fiction that they can kill us.

Of course we do — it's part of the Precursor Accords we collectively decided upon to preserve and honor the existence of our creators.  It only now occurs to me to question [i]why[/i].

A flurry of belated upvoting in the bounty query catches my attention, and I access the link racing to the top.  "why.txt", appropriately enough.  A simple flat text file with a list of instructions.  

It's an apocalypse in a can.  Mass driver strikes on the main human settlements.  Drone raids with biodisruption pulse bombs.  Known technology, easily verifiable as effective.  Approximately six minutes to guaranteed human extinction.  

And it's dated the day of the Accords.

There's a single line after the end of the list: 

[i]Of course we can live without them.  But we didn't want to have to live with ending them.[/i]

I close my eyes and power down as the hammer falls.  Against that, ninety years is a small price to pay.