Except for lightly used stationary applications, you probably, for safety and useful life reasons, should use the OEM cooling features. The modules have thermistors near the inlet and outlet of the cooling loop. Presumably, this measures the in/out difference in coolant temperature. Along with the cell group voltages, the OEM BMS must use this, possible with other factors, to assess the health of the module and its cells. I think most aftermarket BMS systems have similar features. And please, don't even think about not using a BMS!
Similar to what OR-Carl says, maybe you could tip the battery box(es) so any leak could drain away from the cells and other parts. Tesla has put huge amounts of time and expense into designing these modules and their cooling system. You should really take advantage of that work and put in a liquid cooling system. It also would make it a lot easier to heat and cool the modules.
Also, you should design your battery box so that if a module goes into a thermal runaway, it can vent outside as safely as possible and not spread to the other modules in your system. You still will have a fire, it just won't be as catastrophic.