It appears the reversers were a long time in the "in-transit mode" when for all practical purposes they were stowed. So if you glance at the indicators at the right time the fact that they are amber might lead you to believe the reversers are behaving normally and will be available in a second or two. Obviously you don't wait forever but if your attention was drawn to the speedbrake problem at just the wrong moment would that delay the point at which your realise the reversers aren't working either. Cycle the reversers and are you at 12 seconds yet?