Since they were soldiers that served in the army, the special forces, and the royal guards, it was only natural that they would be able to do this.
It was only low level magic, but it was enough when they combined it together.
If this was land, then it would have been easier since they would be able to throw in some kind of smoke pouch to fill up the house. Once the house was filled, it would be very hard for whoever was inside to remain in there.
But under the water, it was hard since smoke wouldn't actually last in the water.
Instead, there was something else that they used.
With all of the low level water spells that they cast, there was this bubble that formed around this house.
This bubble completely isolated this house from the rest of the ocean, creating what seemed to be an isolated environment.
