The escape key is always needed for terminal programs like vim.

lib/TerminalDisplay.cpp

@@ -2660,6 +2660,7 @@ bool TerminalDisplay::handleShortcutOverrideEvent(QKeyEvent* keyEvent)
       case Qt::Key_Backspace:
       case Qt::Key_Left:
       case Qt::Key_Right:
+      case Qt::Key_Escape:
         keyEvent->accept();
         return true;
     }