The initial run of the pump should bring the line pressure up to the 3 bar (44 psi) rating of the fuel pressure regulator. If the computer doesn't get a crank rotation signal then the pump is shut off for safety reasons.I'm seeing it jump to between 10-15 PSI and then immediately fall off.
The pressure in the lines should then be maintained for a good amount of time unless there is a leak somewhere in the system that relieves the pressure. A leaking connector or split fuel line is usually the culprit. A faulty pressure regulator or a stuck open injector/solenoid would also provide a leakage path. The pressure should not fall off so quickly.
The fact that the lines are only reaching 15 psi also tells me there's a leak in the system.