Not trying to explain, excuse, just experience in the same company, aircraft and operation.
We don't do "Cat A" profiles in singles in the company. We're taught to 'vertical' in and out of LZs, maintaining vertical profile while below "X" feet above all obstacles. I find it's easy to drift somewhat doing this, especially at night. Further complicating this, the company discourages turns in the accelerate/climb until above yet another "X" feet agl. Leads to turns to align with departure path in the hover vertical, easy to drift off the vertical, again, especially at night.
It's impossible to get useful depth by looking at the wires of the size and distances involved in EMS in the daytime, much less at night.
It's easy to inadvertently back in the vertical climb, most or your cues are out front and at an angle, so holding the angle means you're backing up.
The company SOP to compensate for this is 'all eyes outside' in flight except in cruise. The patient is stable enough to transport and doesn't require medical crew attention during takeoff and landing, or the brief will specify otherwise, and that's unusual.
Our aircraft generally have a fair amount of lights, including some directed to
the side, "scene" or "doghouse" lights. They don't seem to have been used here, except for the landing or direct-able searchlight. My perception is that the company discourages use of the scene lights for night departures. That could be wrong because I'm a crusty old... well, anyhow, I'm set in my ways and know what works for me.