It depends. If the voluntary tactical team is something for which they are paid (i.e., regular pay, not necessarily extra pay), then it can be considered a work function. The training itself may also be considered a work function but the disclaimers signed should give you the full story on whether it would or could be considered as a workers compensation eligible injury. Better to apply and be turned down. You should also consider simultaneously applying for short term disability but the short term disability may be a safer bet as far as payout is concerned.