Towards the end of ST:TNG's Time's Arrow, Pt. 2, Captain Picard is stuck in 19th-century San Francisco, and the rest of the crew is on the Enterprise. Riker wants to go back in time with an away team to get Picard. The security-minded Worf proposes that they instead must destroy the alien habitat that houses the time gateway. Riker is convinced when Troi agrees with Worf, and he says
Power up the photons, Mr. Worf. Alert me when they're ready.
One commercial breakAn unknown amount of time later, Worf is at the tactical station and tells Riker that he's "set the photons...". Riker gives the order to fire, and Worf says it will take another minute (!) until the sequence is ready to initiate.
Meanwhile, Geordi's down in the lab with the unconscious Data who, script-wise, has to wake up and stop the bombardment because it'll backfire. Obviously that's the out-of-universe explanation for this delay: the dramatic tension of the audience knowing that firing the torpedoes will be disastrous.
Is there an in-universe explanation?
Waiting a couple of minutes to "power up", program, and then "initiate" the photon torpedoes in a battle would be deadly. What's taking Worf so long with this task?