I don't think Tony necessarily has to be working at full efficiency for this. Say Tony is taking a break when he gets a text from support, "Big Client X is really unhappy, looking for your help on this". He texts Gloria, "grab me previous interactions with X". Maybe he needs financial info that Gloria doesn't have a record of. "Dan, Tony needs to know Y, send me the info?". A chain like this could easily form a graph of tens of people, and will require back-and-forth.
You could imagine a scenario where everyone at the company is taking a break when X has their issue, and that's the best case scenario. Instead of everyone off doing their own thing, they're slacking off but ready to help. The combined context switching in an extreme case like this could be hours or days.
It always reminds me of a fire brigade or an army. You want the firefighters to have lots of slack so that they will be available when there is a fire. On the other hand, having people sitting around "being ready" is costly and there is some optimum amount you need.
The timescale makes a huge difference here. Firefighters need to be next to their equipment to respond to an emergency. US army reservists “One Weekend a Month, Two Weeks a Year” is understating things, but they can hold down a full time job when not called up.
What I meant was that both professions are good examples of "slack-full" professions. They can still be considered to be doing their job well even if they're not actively fighting (either fires or the enemy). If they're consistently inactive they may get a reduction in numbers, but I've never seen anyone seriously suggest to abolish the fire brigades.
You could imagine a scenario where everyone at the company is taking a break when X has their issue, and that's the best case scenario. Instead of everyone off doing their own thing, they're slacking off but ready to help. The combined context switching in an extreme case like this could be hours or days.