Let’s do it:

The phenomenon that causes divers to be trapped is called differential pressure, or Delta P. It requires surprisingly little Delta P to trap divers in such a way that they can’t free themselves.

The formula is simple: F=Δp⋅A Δp = Differential pressure, A = the area the differential pressure acts on, in our case the cross sectional area of the pipe.

#Example

30 cm pipe => A = π⋅(0,15)² Delta P only (!!!) 0.1 bar (= 10 kPa).

F = 10,000 Pa ⋅ 0.07 m² ≈ 700 N. This equals roughly 71.38 kg of weight.

#Now, let’s try this with the numbers above. Unfortunately, we don’t know the diameter of the pipe so let’s again assume 30 cm.

Δp = 21.375 - 14.7 psi = 6.675 psi ≈ 0.46 bar = 46 kPA

F = 46,000 Pa ⋅ 0.07 m² ≈ 3250 N. So you would be sucked to this pipe opening with a force of roughly 330 kg.

#For fun, let’s assume a 50 cm diameter pipe:

F = 46,000 Pa ⋅ 0.196 m² ≈ 9020 N. This equals roughly 920 kg of pressure.

There is absolutely no escape here and I think it’s safe to assume the diver would be sucked through that pipe.