Sometimes you want the player to use fast camera movement in a map, but that doesn't mean they're going to. With this, they'll have fast cam regardless of their settings.
First, place a timer. Set Launched on start to Yes, Max calls to Infinite, and Delay to 0. Then place a trigger, set Enabled to Yes, and Max calls to Infinite (remember to link the timer to the trigger). Finally, copy and paste the following into the blank trigger using the Edit triggers as text button.
VarSetValueIfUndefined( "fast_cam", "0" );
VarAddValue( "fast_cam", "1" );
next if VarA == ValueB( "fast_cam", "1" );
Zoom( "100.000000001", "0" );
continue if VarA == ValueB ( "fast_cam", "2" );
Zoom( "100", "0" );
VarSetValue( "fast_cam", "0" );
If you have a different zoom set for the map, then you'll want to set both zoom parameters equal to that, but with the added decimals at the end for the first zoom action.