diff --git a/src/platform/sw/register.ts b/src/platform/sw/register.ts
index 89878ca..7e05484 100644
--- a/src/platform/sw/register.ts
+++ b/src/platform/sw/register.ts
@@ -14,7 +14,9 @@ export async function registerSW(): Promise<SWRegistrationResult> {
     return { status: "unsupported" };
   }
 
-  // Do not block app boot — register after load, catch errors.
+  // Unregister all existing service workers first to ensure clean update
+  await unregisterAllServiceWorkers();
+
   try {
     const reg = await navigator.serviceWorker.register("/sw.js", { scope: "/" });
     return { status: "registered", registration: reg };
diff --git a/src/ui/views/emergency/emergency.ts b/src/ui/views/emergency/emergency.ts
index c369058..c4f10a8 100644
--- a/src/ui/views/emergency/emergency.ts
+++ b/src/ui/views/emergency/emergency.ts
@@ -136,6 +136,25 @@ export function createEmergencyView(
   urgent.append(text("p", "Tap to call. The number is also selectable for copying."));
   section.append(urgent);
 
+  const shareBtn = document.createElement("button");
+  shareBtn.className = "emergency-share-btn";
+  shareBtn.textContent = "Share emergency info";
+  shareBtn.setAttribute("aria-label", "Share emergency information with others");
+  shareBtn.onclick = () => {
+    const textToShare = `Emergency: ${services.emergencyNumber}\nAddress: ${address.lines.join(", ")}\nFirst Aid: ${services.firstAid.location || "See venue"}`;
+    if (navigator.share) {
+      navigator.share({ title: "Emergency info — Lumen", text: textToShare }).catch(() => {
+        /* user dismissed the share sheet */
+      });
+    } else {
+      navigator.clipboard?.writeText(textToShare).catch(() => {
+        /* clipboard blocked — the alert below still shows the text */
+      });
+      alert("Copied to clipboard: " + textToShare.slice(0, 80) + "...");
+    }
+  };
+  section.append(shareBtn);
+
   const contacts = document.createElement("section");
   contacts.setAttribute("aria-labelledby", "emergency-services-heading");
   contacts.append(heading("emergency-services-heading", "Contacts"));