Heidi Brayle, a location manager for a film company, asks Jonathan for permission to film in and around his windmill at the bar of a social event while loud music is playing. The next morning the film crew turn up at his windmill to start filming. In reality, the process of location management is far more formal, involving negotiating contracts and a great deal of planning and several meetings. It certainly wouldn't be done without even getting Jonathan's signature on a single document.
If Masson committed suicide and tried to frame Downey for murder, then surely the time of Masson's death would be taken into consideration. (In 'Black Canary', a paramedic was able to tell from the onset of rigor mortis the approximate time of death).
And since Downey was waiting for the meeting for 30 minutes or more with the others outside the room, then it would have been proven that Masson died at the same time as Downey and the others were outside the room, therefore clearing Downey.
And since Downey was waiting for the meeting for 30 minutes or more with the others outside the room, then it would have been proven that Masson died at the same time as Downey and the others were outside the room, therefore clearing Downey.