The only direct interaction guards need to take with prisoners is food delivery and laundry transfers which occurs through the "bean slot" beneath the prisoners view screen. The desk folds down to allow the prisoner to be handcuffed through the slot, if necessary. Otherwise there are built-in wall shackles. Pesky prisoners may be fitted with a variable gravity vest. Practically impossible to get out of, guards can vary the load of the vest from 1G (off) to 6 G, bringing the prisoner immediately to the ground in case of trouble.
Not all brigs have space for a separate shower facility, so some cells may have the unit shown above, which includes a shower.