a spoof, really? This same user has a second video with 2 coils, there you can see the core moving. Yes possible a door chime coil. I have one here (Friedland) but it is 8V AC, although I see a diode inside, maybe it will work on 9VDC also? It looks more like a solenoid the coil is 25x15mm, the core moves about 10mm, it makes me thinking, why not stick a small permanent magnet to the end of this core and let this do the triggering? But then there is still the amperage, I think such a coil needs 1A or so? The 9V will not last long then.
Like you say maybe it is better to go beyond the reed, I have another look at it. Why establishing the + or - rail on the reed terminal? To know how to connect it in the transistor circuit? If this is not possible maybe I can use the contact of a reed relais then, parallel over the old reed switch?