diff --git a/webapp/path_navigator.html b/webapp/path_navigator.html
index 1fb5a03..f5c8d2b 100644
--- a/webapp/path_navigator.html
+++ b/webapp/path_navigator.html
@@ -352,6 +352,14 @@
                             'border-width': 0,
                         }
                     },
+                    {
+                        selector: 'node[sirenActive = "true"]',
+                        style: {
+                            'border-width': 4,
+                            'border-color': '#ffffff',
+                            'border-opacity': 1,
+                        }
+                    },
                     {
                         selector: 'edge',
                         style: {
@@ -462,6 +470,20 @@
                     })
                 }).then(r => r.json()).then(data => {
                     console.log('Playing on', destination + ':', data.frequency.toFixed(2), 'Hz on voice', data.voice);
+                    
+                    // If playing on siren, add white circle around node for this voice
+                    if (isShift) {
+                        const nodeColor = node.data('color');
+                        // Find any existing node with same color that has sirenActive and remove it
+                        cy.nodes().forEach(n => {
+                            if (n.data('color') === nodeColor && n.data('sirenActive')) {
+                                n.data('sirenActive', '');
+                            }
+                        });
+                        // Add sirenActive to clicked node
+                        node.data('sirenActive', 'true');
+                        console.log('Added sirenActive to', node.id(), 'color:', nodeColor);
+                    }
                 }).catch(err => {
                     console.log('Error playing freq:', err);
                 });
@@ -716,6 +738,7 @@
                     // Count differences in dims 1, 2, 3
                     let diffCount = 0;
                     let diffDim = -1;
+                    let broke = false;
                     
                     for (let d = 1; d < hs1.length; d++) {
                         const diff = hs2[d] - hs1[d];
@@ -723,12 +746,13 @@
                             diffCount++;
                             diffDim = d;
                         } else if (diff !== 0) {
+                            broke = true;
                             break; // diff > 1 in this dimension
                         }
                     }
                     
-                    // Check if exactly one dimension differs
-                    if (diffCount === 1 && diffDim > 0) {
+                    // Check if exactly one dimension differs AND loop didn't break early
+                    if (!broke && diffCount === 1 && diffDim > 0) {
                         // Calculate frequency ratio
                         const diffHs = [];
                         for (let d = 0; d < hs1.length; d++) {
@@ -975,6 +999,8 @@
                     body: JSON.stringify({ soft: true })
                 }).then(r => r.json()).then(data => {
                     console.log('Soft kill sent (20 Hz)');
+                    // Clear all siren circles
+                    cy.nodes().forEach(n => n.removeData('sirenActive'));
                 }).catch(err => {
                     console.log('Error sending kill:', err);
                 });
@@ -986,6 +1012,8 @@
                     body: JSON.stringify({ soft: false })
                 }).then(r => r.json()).then(data => {
                     console.log('Hard kill sent (0 Hz)');
+                    // Clear all siren circles
+                    cy.nodes().forEach(n => n.removeData('sirenActive'));
                 }).catch(err => {
                     console.log('Error sending kill:', err);
                 });