Something I have learned, slowly:

As a cishet white American man - things I have no choice in - my existence alone can be triggering for some people.

Especially in high stress situations.

There’s not much I can do in these cases except to try to take up less space, talking less and so forth, in such situations. Then wait for them to let me know when they are more comfortable. And if they never are and if we both don’t have to be there, then just leave and give them their space permanently.

And to not be bitter about it. They don’t want to have had their history that led to them being triggered by my existence either.

It’s not easy to remember that last bit but it’s important.