I'm glad.Most BPs are pretty tolerant (mellow) anyway. What MOST snakes hate about a "soak" is the loss of traction- you want to keep the water shallow (not higher than their height is); you don't want to force a snake to keep swimming- most will go thru the motions instinctively even in shallow water, but if they can feel some traction- like a rubber mat or even a small towel under them in the water, that helps reduce their stress & panic too. And keeping the water with just a hint of warmth helps too- not cold or too hot.* Use a thermometer to check- don't rely on how it "feels" because our bodies are 98.6*, so to feel "warm" to us means it's too warm for the snake. Water temperature can be very deceptive. And I'm sure you handled him gently thru this- that all helps too.
BTW, with a drop or 2 of soap added, also make sure the snake doesn't drink the bathwater- that would upset their digestion. Another reason to stay "right there" with the snake.