The "solo mentality" is something that I need to understand better. Do you mean to be self-reliant
Solo in the context of DM isn't self reliant in the normal sense. By that I mean having an OOA since you're with guests/other divers, you have access to plenty.
But as a DM/Instructor you are diving alone. What I mean is this: It's quite probable if something goes wrong your "buddies" dont' have the skills or experience to help. No one underwater is asking YOU if you're okay triggering you to check your gas etc and before someone jumps in to the check gas comment, often new DM's are so focused on their guests and actively guiding they get tunnel vision.
Pre dive, as a dive pro you need to get yourself into a rhythm. I personally get my gear assembled and checked way ahead of time (remembering to shut off the gas and vent the lines). As soon as students/guests are on the boat my focus is on them, both assisting and answering whatever questions they have or solving problems.
If you want real distraction, take a small group of 4 students off a boat on OW dive 1
When it's time for you to get your kit on (you're generally the last and don't wish to keep people waiting you want to be sure it's ready and fully checked. The reason I vent my lines (and tach my DM's to do so also) is not because of gas leaks, but simply in a rush it's too easy to forget to turn on yoru tank, seeing a SPG at zero lets you know, where as it's too easy to glance at an SPG that shows pressure and jump in with your gas turned off.
I've never jumped in with my gas off, but more than once had to turn my gas on once my kit is on my back. Distractions.
This is the main reason it's different from Tech, you're not going calmly going through a checklist with team members, so you really do need to be mentally prepared and adopt a process that allows you the time to get yoru gear sorted while giving yoru students/guests 100% focus
Unfortunately some people get their pro card and think it makes them invunerable when actually the opposite is true