In a case where electrical current leakage from the circuit occurs,
the gfci would do the following:

The GFCI shuts down the circuit when it senses a current leakage.

Explanation:

The ground of a circuit should truly be ground. But if the ground circuit is not truly ground, then someone could get shocked. The GFCI monitors the possibility of current flow to ground. If this occurs, then the GFCI stops all flow of current, for safety reasons.

It also monitors if the current flow is interrupted. Say you drop something that is plugged in, into a sink of water. The GFCI should note the current loss, and shut down the circuit.

GFCI stands for: Ground-Fault Circuit Interrupter