Does a hero have to do the same actions as the unit they are attached to. The rules identify a unit is the miniatures on the unit card instead of a squad. A unit is given two actions but it doesn't say that a hero has to use the same actions. (ex Lara is attached to the Heavy Flak Grenadiers, who use one action reloading their weapon and their other action as nothing. Can Lara do a sustained attack while her troops reload their guns.)

While a hero is attached to a squad, they are considered to be a single unit. Therefore they share their actions. If the Flaks reload, Lara also spends one action just looking at them. Likewise if Rosie is attached to the Crack Shots and uses her Tank Head, the sniper can't make a Sustained Attack.

Therefore, there are points in the game when it could be advantageous to suddenly dettach the hero from the squad, just so one won't be weighed down by the actions the other one must take. You could dettach the Flaks and have them reload and fire, then afterwards have Lara make a Sustained Attack. Though she won't be able to rejoin her squad…