Even when i was a kid and didn't know anything I didn't understand them. Turbos are oil fed and coolant fed. So, as long as you didn't just get off of a 45 minute wot haul it's going to cool down as far as it's going to cool down by the time you find your parking spot.
Compared to 1500° at wide open run the 700° at low rpm and idle is frigid and will bring it down quickly coupled with the oil and coolant both under 220°, and the incoming air from the intake that's 100°.
So you just finished your wide open run Colin McRae style from home to work over about 39 miles of dirt, gravel, pavement and snow, you see the parking lot you park in up ahead. you grab your ebrake and fly into the parking lot sideways engine hammering off the Rev limiter with an anti lag system cracking off like rounds out of a m60. You toss a roll of dimes out the window as you pass by the parking attendant booth to pay your daily fee. Continuing on you grab that ebrake again and whip a massive shitty into a reverse slide backwards into a parking spot and shut down the engine immediately. Maybe you'll need a turbo timer.
You just drive like a normal human, or above average toolbag you'll still be fine.
OEM turbos have been using water cooling for quite a while. The aftermarket options weren't commonly water cooled until the turn of the millennium. A lot of the DSM stuff were only oil cooled, Mitsubishi turbos not included.