ex-egll, surely it is more likely that ATC instructed 565 to go around after it was clear that 521 was not going to get airborne again otherwise he would have had two aircraft climbing to the same altitude on same heading and in close proximity.
Agreed, and that's what the tape indicates. In listening to the recording my initial thought was the controller saw EK521 perform a manoeuvre that appeared to be the start of a (pilot initiated) missed approach. The controller then gave EK521 the missed approach routing (NOT an instruction to commence the missed approach). At this stage EK565 was still on approach awaiting landing clearance. When the controller noticed that 521 had hit the ground, among many other things that had to be done, missed approach instructions were then issued to EK565.
As for having two aircraft on the missed approach it shouldn't be too much of an issue, they were separated coming down the approach, they should remain separated going on the missed approach, but a quick turn (when safe) or an altitude restriction should keep it all good.