Could you please clarify your question? Are you asking if there has to be exactly three employees volunteering in the scenario in question -if F volunteers?
If F volunteers, we can infer that T, M, R are out. Since R is out, L must be in. S/V rule tells us that at least one of them must volunteer or both, they cannot both be out, but they can both be in. So if F volunteers, we could either have the following possible scenarios:
FLSV FLS FLV
Let me know if this answers your question.
@chris_vaOctober 1, 2019
Thanks so much, I'm still getting the rules down for these. That helped a lot.