I vote another "unwanted die roll in combat." I am not a fan of reaction rolls. I let the human player figure out what they are doing, not the die roll.
How would you handle it if the die roll says "stay and fight" when the actual human player wants to find a safe place to stay out of the way of bullets and assorted other incoming stuff?
One of the things I really like about RPGs is they give us a chance to live a story that is only ever going to be a fiction for us. Traveller is one of the apogees of that whole concept.
So when we play a game, stuff can happen that we're just not going to react to in the same way people do in real life. Bad stuff happens, dangerous stuff happens, and scary stuff too, and people don't behave they way they'd like to.
I remember doing a course one time and the chief instructor had an adage he kept repeating:
People don't rise to the occasion, they sink to the level of their training.
Now, he was talking about the situations we were training for which were a little more stressful than the average disagreement over the optimum colour of toast. Some of those seem to have turned up in scenarios we've played, but I'm really happy to leave it that way.
So, when I consider asking players to make a roll to see if they can keep all their sheep together long enough to make a skill test, it's about them being in an unusually stressful, or potentially outrageously dangerous moment when anyone would struggle to focus on the task at hand. Where they are likely to sink to the level of their training.
I agree with you insofar as don't think every stressful situation demands a reaction test like that. And I agree that reaction tests slow down role playing at times when we want the tempo of the game to be high, that they shouldn't be de rigueur but only when the ref requires it as a mechanical element that can provide another indicator to the players of what's happening to their characters. But I'm not really for characters standing and fighting, or calmly fixing the jump drive, or whistling Bach (the elder) as they try to rapidly drop their badly-holed almost-empty-of-bodily-fluids companion into the emergency low berth so they can be delivered to medical help before they arrest, when that's just not what would be seen in the real world. If Traveller is meant to be hard sci fi, then there's got to be mechanics to allow for some of that real stuff in it.
That shouldn't stop you from doing any of that though, 'cause your game's happening in YTU. Plus it's just a game, so we should all run it the way that's going to provide the most enjoyment for ourselves and our players. I just wanted to run through my reasoning and after seeing it in pixel-and-white see if it still made sense.