diff --git a/docs/re/mission-freeze-signin-dialog.md b/docs/re/mission-freeze-signin-dialog.md
index 32d819bf..9115d8c6 100644
--- a/docs/re/mission-freeze-signin-dialog.md
+++ b/docs/re/mission-freeze-signin-dialog.md
@@ -67,3 +67,35 @@ Checking that distinction is what led to the dialog mechanism.
 scans are still 0 at screen 10, so the remaining screens are menus (mission
 select, briefing, ready room). That is now ordinary navigation work, not a
 blocker.
+
+## ⚠️ The fix must be applied at LAUNCH — `nav_to_flight.sh` cannot do it
+
+`nav_to_flight.sh` contains **no** `run-canary` invocation: it drives an
+*already-running* emulator. So whether a profile is signed in depends entirely on
+how the caller launched it, and every `nav_to_flight` run in this session was
+launched with a bare `run-canary --apu=sdl …`.
+
+**That is why those runs froze**, and it is worth stating plainly because the
+script prints `signing in profile B13EBABEBABEBABE` — which comes from the
+emulator's own startup, not from the script arranging it.
+
+    run-canary --apu=sdl --logged_profile_slot_0_xuid=B13EBABEBABEBABE   # then nav_to_flight.sh
+
+## 🔴 Refuted: "each screen loads its own `GP_*.pak`"
+
+A plausible way to get a *real* screen identity — watch which pak the game opens
+— does not work. With full file logging, the only names that appear are at boot
+(`sound.p0x`, `tables.p00`, `hidden`), and nothing new is opened when the UI
+moves between screens. The paks are opened **once** and read by offset
+thereafter, so file I/O carries no per-screen signal.
+
+## ⚠️ Boots are flaky, independently of this bug
+
+One launch in this iteration never reached the title at all: progress counter
+stuck at `0`, screen black (mean `0,0,0`), guest churn **0.001 %**. That is a
+*different* failure from the sign-in freeze — which stalls *after* the main menu
+with the counters already advanced — and it matches the flakiness
+`canary-scripted-input-traps.md` already documents ("(A) at the title is accepted
+on roughly half of boots and nothing observable predicts which"). **Distinguish
+them by the counters**: sign-in freeze stalls with counters advanced past the
+title; a bad boot never leaves 0.