Hi mate :)
On rulebook 2.0 page 19 is indicated that players use their sentry tokens in intiative order by taking turns. This means:
Player with initiative activates 1 sentry token
Player 2 activates 1 sentry token
Player 3 activates 1 sentry token
Player 1 activates second sentry token
and so on.
Unused sentry actions... does each player resolve all his sentry actions in initiative order, or, do players resolved 1 sentry action at a time in initiative order?
Page 19 which discusses this is a little unclear, but the difference is huge in game turns :)