Maxalt, The 732 was probably cleared to line up and take off as it would have otherwise acted as an obstacle (potential) to the incoming learjet. It was probably close to the runway on the taxiway and ATC saw it more fit to clear it away before the learjet touched.
BTW, the 742 is a hard one to touch and hold level on finals in non standard conditions. Can often depend on the gyration swing and all else.
Rgds.