I'm shitting it but I can't do nothing
This exactly what you can do and, unless you are the team leader or manager of this "senior colleague", it's what you should do as it's not in your remit to take him to task for a comment that, while it may have left you "speechless with shock and fury", doesn't appear to have had the same affect on others who were present.
Unless he's got form for being more honest outspoken than most, in which case you should leave well alone, I suggest you approach him when no-one else is around, perhaps over the coffee machine, and say something on the lines of 'were you having a trying day on as it's not like you to be insensitive and I found it odd that you said it would have been irritating rather than harrowing for to accompany to the police station?'
Alternatively, now you are aware that he can be a plain speaker, you could wait to see if he makes what you consider to be another unacceptable comment and challenge him at the time.
That said, I take the view that those who are in the frontline of client/customer relations shouldn't have to watch their language when they are conversing with colleagues who are aware of the challenges that such roles present. You may have found a certain situation harrowing; he would have found it irritating. Both of these viewpoints are subjective and he's as entitled to express his opinion as you are.
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