From the moment Maria whispers "Mayday Mayday Mayday" on I-285 West at 11:42pm to the moment she's safe in a locked Camry with state troopers taking her statement. Six use cases. Eleven minutes fourteen seconds. One human voice on the line before the pass.
Module 1 earned the right to be on the phone. Module 2 has eleven minutes to keep a stranger from taking the driver with it.
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Speed is the product
Every second between "Mayday" and a calm voice on her line is a second the passenger can move, grab, or escalate. The system is engineered backward from a 30-second P95 budget.
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One human voice
The AI opens the line in six seconds. A real human — Jordan, ex-911 dispatcher — owns it by 24 seconds. De-escalation research (FBI BAU, Police Foundation) shows trained humans outperform LLMs in crisis dialogue, every time.
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Stealth is non-negotiable
UC-6 happens with zero observable cue to the passenger — no screen flash, no haptic, no app switch. If the attacker notices the trigger, the trigger has failed.
UC-6
The trigger (t = 0)
Actor: Maria (voice) → Mayday daemon · 11:42pm, I-285 West, both hands on the wheel
2On-device wake-word model (Picovoice) scores audio against her personalized embedding. Confidence 0.94 > personalized threshold 0.86.t = 0.72s
3Silent handoff: ringer muted, haptic off, screen stays at current brightness (no flash), Lyft driver app stays foreground (no app-switch tell). One long, very soft haptic pulse fires once so Maria feels confirmation without the passenger noticing.t = 0.80s
4Live Activity chip appears, tiny and dim: "● Recording — Mayday active." Tap = status; long-press = safe-word.
5Parallel fork: UC-7 (capture), UC-8 (broadcast), UC-9 (voice call) all triggered simultaneously — never sequentially.
Acceptance criteria: End-to-end trigger latency (last syllable → capture start) ≤ 1.0s P95. Passenger cannot detect the trigger from screen, sound, or vibration. If trigger is in error, safe-word stops the event within 5s of speaking it.
UC-7
Evidence capture
Actor: Mayday daemon → S3 vault (Object Lock Compliance) · Chain-of-custody from frame one
1Front camera (rear-facing seat cam) + back camera (driver-cam) start simultaneously. Audio 16kHz mono. Resolution 720p to keep uplink ≤ 2 Mbps.t = 1.0s
3Each chunk's hash is appended to an append-only ledger in Postgres (event_chunks table) — this is the chain-of-custody receipt.
4S3 Object Lock (Compliance mode) is enabled on the bucket — even Mayday engineers cannot delete or modify evidence before the legal hold is lifted.
5GPS pings every 5s, IMU at 50Hz, barometer at 10Hz — all appended to the same event log for forensic reconstruction.
Edge cases:
• Cell drops — chunks queue locally; upload resumes automatically; ledger records gaps.
• Storage full — older chunks drop first; the current event is never dropped.
• Phone damaged — captured-so-far is safe in cloud; on-phone vault preserves last 30 min locally until reconnect.
2Twilio Programmable Messaging sends SMS in parallel. Template: "MAYDAY: Maria triggered Mayday at 11:42pm. Live audio + map: mayday.app/e/<token>. Tap to listen. Reply SAFE to acknowledge."
Sent from short-code 884-233 (MNDAY).
3Each link is a signed, no-login web view showing: live GPS pin (5s update), current speed/heading, optional live audio (WebRTC opt-in), and three buttons — Call Maria / I'm calling 911 / She's safe — disarm.
4Push notifications to contacts who have the Mayday app (Maria's partner does — UC-1 referral).
5If social blast enabled (it isn't here): a single Mastodon/X post via her pre-authorized template — Maria left it off during UC-3.
Acceptance: SMS delivered to ≥ 4/5 contacts within 5s (Twilio median ≈ 1.4s in US). Live audio link is opt-in per contact — default opt-in for those marked "always listen" in UC-3. Failure modes: Twilio down → Bandwidth fallback → Apple/Android push with SMS retry. Contact phone off → SMS queues; voicemail fallback requires user pre-consent (avoids wiretap exposure).
UC-9
AI voice call & operator handoff
Actor: Mayday AI + BPO operator + Maria · The bet no other safety app makes
1Mayday places an outbound Twilio call from a Mayday-owned number +1 (404) 555-MDAY to Maria's phone. Audio auto-answered at low volume so the passenger may not notice immediately.t = 4s
2AI voice agent (OpenAI Realtime, custom safety prompt) opens: "This is the Mayday Safety Service on a recorded line for Maria. Maria, you triggered Mayday. I'm here with you. I can hear what's happening. Nod if you want me to stay silent."t = 6s
3In parallel, AI opens a Twilio call to the first available BPO supervisor in the 24/7 queue. Live audio + GPS from Maria's phone pipes to the supervisor's web console via LiveKit.t = 4–10s
4Supervisor Jordan (Atlanta-based, ex-911 dispatcher) accepts. AI summarizes: "User Maria, rideshare driver, threat in progress, passenger male late-20s, location I-285 West mm 22, speed 64 mph, audio: shouting."target 18s · actual 24s
5Jordan takes over voice. He addresses the passenger by inferred name from Lyft manifest: "Hey, this is Jordan with the Mayday Safety Service. I'm listening live. We've already contacted police and they have your plate. Maria is going to pull over at the next well-lit exit. Stay calm."
Verbal de-escalation — shown to reduce assault probability in transit settings.
6Jordan clicks DISPATCH in console → UC-10.
Why human, not AI:
• De-escalation research (Police Foundation, FBI BAU) shows trained humans outperform AI in crisis dialogue.
• Operator judgment on "is this real?" is faster and more accurate than any 2026 LLM.
• Liability: a licensed human dispatcher on the call is the legal lever insurance + courts accept. Acceptance: human voice on Maria's line P95 ≤ 30s. Recording chain-of-custody unbroken from Maria's phone to operator's headset.
UC-10
911 dispatch
Actor: BPO operator Jordan + RapidSOS + Fulton County PSAP + Georgia State Patrol
1Jordan clicks DISPATCH. RapidSOS Ready payload pre-built: GPS (33.7891, -84.4692), speed 64mph, last 60s audio clip, user profile (Maria, female 31, no weapons, no medical), vehicle plate, attached evidence link.
2RapidSOS pushes to the appropriate Fulton County PSAP. The 911 dispatcher sees the case auto-populate.
3Jordan stays on line with Maria. Simultaneously calls 911 voice via dedicated RapidSOS line that supports audio relay. He relays: "Mayday Safety, calling on behalf of Maria [last], rideshare driver, currently westbound I-285 mm 22, passenger threatening, audio relay active, plate Georgia [ABC-123]."
4Maria, hearing Jordan's calm voice, signals she can pull over. Jordan coaches her: "At the next exit, well-lit gas station. Stay in the car, doors locked, engine running."
5Two Georgia State Patrol units dispatched.ETA 4 min
6Maria exits at the well-lit Shell station. Passenger sees the lights behind him. He bails out of the car and runs; troopers pursue.
7Maria is safe, in her locked car, on the line with Jordan. Troopers return to take her statement.
Edge cases:
• PSAP rejects audio relay → fall back to text-to-911 + voice-only relay to Maria.
• Cell signal lost → last-known GPS sent; BPO continues calling Maria's voicemail with pre-recorded instruction.
• Maria becomes unreachable → escalation: call partners, call Lyft Critical Response Line, then 911 with cell-silent dispatch.
UC-11
Resolve the event
Actor: Maria + BPO + Mayday · ACTIVE → RESOLVING · Total elapsed 11m 14s
1Maria, now safe, says the safe-word: "All clear, false alarm... no, all clear, I'm safe."Voiceprint-verified against her UC-3 model.
2Mayday transitions ACTIVE → RESOLVING. Capture stops. Live audio links auto-revoke in 60s.
3Jordan asks the four post-event questions:(1) injured? (2) medical? (3) Lyft replacement driver? (4) consent to share recording with police?
4Maria says: no, no, yes, yes — injured no, medical no, replacement yes, share yes.
5Mayday generates a one-page incident PDF + full evidence bundle. Links sent to Maria and — with her consent — the trooper on scene.
6Trusted contacts receive: "Maria has resolved her Mayday event. She's safe." + care resources (links to UC-13 in Module 3).
7Lyft Critical Response Line receives structured event JSON for their own internal tracking.
Outcome: Event sealed. Maria physically safe. Recording held under legal hold pending UC-12 (Module 3). Total elapsed trigger-to-resolve: 11 minutes 14 seconds.
Outcome of Module 2
Maria is safe. The recording is already in S3 with a notarized chain-of-custody hash. Five contacts know. A State Patrol report is opening. And the worst part of her night is over — but the next 24 hours are what decide whether she keeps driving. That's Module 3.