Went for my 'free' tire rotation where I bought my tires a year ago.
I removed myself all four wheels in the winter to change my brake fluid -- no power tools were used.

While the shop was removing the wheels they came to get me to warn me that one stud may break. I told them to wait and let me have a look. I asked them to lower the car on the ground so I could give a shot without power tool. I was able to move the nut back and forth but just a bit, it was obviously cross threaded. I gave up and told them to try with their power tool. I should have probably walked away and tried again at home, my mistake, I am biting my fingers, I gave them the green light. Result is that a front wheel stud is now broken on the right side. So I am driving with only four nuts on my front wheel.

(1) Is that OK to drive like that? How critical is it to replace this broken wheel stud and have all 5 in place and not drive on 4 only?

(2) How difficult is it to replace a wheel stud? In Bentley stud replacement calls for caliper and disc brake removal. When I get the caliper out of the way, do I need to disconnect the brake lines from it and hence re-do a brake flush? Parts are cheap, it is only the complexity and true necessity that is keeping me from this fix.
IPD lists the wheel studs at 3 dollars a piece and nuts at 0.95 cents (cheaper at FCP Groton respectively 1.50 and 0.50 cents.

Thanks for your input.
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'89 244DL M47 162K miles