Here is what happens:

When you turn the key to ON, the ECU pulls the fuel pump relay in and the pump runs for maybe three-five seconds.
IF The engine does not start, the ECU disables the fuel pump relay.

The SKREEM is not directly involved in this, if, for ANY reason, the engine does not start, the fuel pump is disabled as a safety item.

Now, since the pump ran for 3-5 seconds, there will be pressure on the fuel system as high as 50psi for some time. If there is not, then the pump did not run or something else is wrong, like a bad fuel pickup in the tank.