Blip:
Now in this case with the visibility being so low, it probably did make sense to clean up as there was no chance of returning for a landing. A diversion to "return airport" was the only option. But imagine if the weather was fine and there was an engine fire, or severe engine damage. You're going to want to return for a landing as soon as possible. Over weight landing? So be it.
How can flying 30 nm away be safer than simply accelerating to flap 5 manoeuvering speed, keeping the aircraft close to the airport, and getting the aircraft back on the ground that much more quickly?
That's why you're paid the big bucks for judgment.
But, you've added "engine fire" and/or "severe engine damage."
More often than not the engine failure on takeoff is not an engine fire, but if it is aren't you trained to keep the engine running until achieving a safe altitude for the circumstances?
As to severe engine damage that isn't necessarily easy to determine.
In any case, being at a flat-land airport on a bright, sunny day is great, so why not cut the OEI profile short and return for landing? The question then becomes, how short do you cut the profile? You probably want to be in approach configuration and at least at minimum maneuvering speed. If this is at 800 feet rather than 1,500 feet, or higher, you have less margin of altitude protection and perhaps a more difficult situation for maneuvering with OEI.
But, we don't fly only on clear days, so the ability to get onto an IAP for return to the departure airport almost certainly requires not less than 1,500 feet, afe, and often higher.