Oops I missed the bit where the OP said she was being asked to do this pregnantly making the dinner surrounded by children whilst simultaneously breastfeeding from a wheelchair.
I thought she just didn't want to do it.
@GintyMcGinty, see Ninkanink's comment.
It's a real shame that people can't see the problem here.
Nobody should be put in a position of letting a team down, or in a position where they are being seen as 'difficult' because of inability to perform in any way in their own time, whether that's 1000 steps on your own time at lunch or going to a strip club with the lads on a business trip.
Setting standards for 'engagement' that have nothing at all to do with what you are paid to do has the potential to exclude large numbers of employees from favourable evaluations.
There are massive problems in an education system where people (presumably women here) can't understand what the problems are with this, what the problems have been historically, and how accepting an employer's right to make this sort of thing (1) possible, and (2) hard to opt out of can and all come back to bite them painfully in the bum, along with others who fall into disadvantaged categories.
There is nothing wrong with simply not wanting to do it, either.
This is not paid time, and her employer is seeking to dictate what she should do in it, with the 'motivational factor' of not letting a team down / facing having to put in work that should be done in the half day off the others will win.