I think 99% of us on here have done the same (if not similar) work that you're doing.
Be it new build/social/commercial etc.
I wouldn't be surprised if the other bloke did do the work he's on about. Plenty of tilers can, and do knock-out 4 kitchens a day, or 20mtrs grouted. But I wouldn't worry about what others can or can't do.
Its getting a balance between the speed and the quality. Don't compromise your quality, but if you try to speed up a little bit, it will come with tilme.
The foreman won't be bothered if the adhesive is dry or not - he just needs it grouted so he can tick the box & then hassle the plumber to 2nd fix or the decorator to get in, and then its another room completed for payment.
I always refuse to grout until its dry, and they'll just have to wait. I usually get the tub & read all the instructions to the foreman about wall prep, application, 24hrs drying etc. They're not ususally bothered, but they get where you're coming from, & they storm off etc. But I wouldn't be bothered about upsetting no-one on site.
As I've said before, this type of work, and the experience, will in the long-run make you a better tiler. Learning all the do's and the don'ts of what goes on..