CTRL+NUMLOCK was Pause, CTRL+SCROLLOCK was Break.
It was not until later that the keyboard was updated with new buttons for newer machines, and got a separate key for Pause/Break, which then still needs to send the same combination of scan codes to simulate CTRL+NUMLOCK and CTRL+SCROLLOCK.
So a more modern Enhanced Keyboard with Pause/Break key sends Pause key as events for pushing Left Ctrl and NumLock, but prefixed with E1, and immediately sends events for releasing Left Ctrl and NumLock, prefixed with E1 to indicate a two key extended sequence. A program ignoring E1 will just see Left Ctrl and NumLock.
And that's why Break is invoked by pushing Ctrl and Pause/Break keys, because it already forces you to manually send Ctrl down event and then the Pause/Break key just needs to send key down event for Scroll Lock, immediately followed by release event for Scroll Lock. The Scroll Lock press and release events in this case are prefixed with E0 to mark them as extended keys, but a program ignoring E0 will see just Scroll Lock with Ctrl held down.
Please note that these scancodes are the original scancodes used by BIOS, not scancodes communicated on keyboard wire, as the later keyboards use different scancodes that are translated to original scancodes by the motherboard keyboard controller.