For all the Commanders regretting Trahearne's death...
Anet SHOWED US what it would look like if we hadn't!!!
In the fight against Mordremoth, for characters who didn't join an Order to get an Order mentor ghost to fight... Trahearne shows up instead. His aggro line is a corrupted version of "this won't end well." It's re-voice acted and everything, more hostile, all that. It's "this won't end well - for you." It's chilling. I hate it.
By the actual canon, the Commander never sees this, because it's technically just a mechanic for players who haven't played the PS. But I headcanon that this still happens for the Commander, because it makes too much sense not to.
Its a lil foreshadowing, firstly, of the concept of a corrupted Trahearne. It's quite possible that when Trahearne is requesting death, Commander has a flashback to the 2-minute version of corrupted Trahearne they met in the mindscape. For some Commanders, that may have been what it took to get them to do the deed.
For others... we have the Second Vision while healing Caladbolg.
In the First Vision, with Riannoc, he was himself and perceived you as a threat, so you fought until he could see you clearly, and then you dueled.
With Trahearne, he's is in corrupted mode again. He attacks you with the same aggro line "this won't end well... for YOU."
A grieving Commander is going to get horrible flashbacks from this, but is also going to get shown quite viscerally what a corrupted Trahearne would be like, in a way they can appreciate better since they've actually faced that idea for real and had to deal with it.
Ideally, the Commander would realize: It's a good thing he didn't become this. The very idea of becoming this would destroy him, as someone who cares so deeply about thought and free will.
This is reinforced when he comes to himself after the battle, speaks to the Commander for a moment and confirms, yes, the Commander did right. Then they duel on friendly terms (yknow to overwrite the trauma from five minutes ago).
Anyway there's an angle you can take with healing. Anet is cowards to try to shove it all under the rug and address the whole thing so quickly, but if you have multiple Commander timelines, this is an option. Or a step. Or an angle.
Me, my Comm is too stunned, shocked, and traumatized for any of this to really register. Timing, yknow.
But it's a thought and it's a thought that hurts.