In this work, we are developing a custom-built broadband laser source in the Mid-LWIR range by combining several high power FP-QCLs for a single snap shot application. To minimize temperature variation or reduce the thermal load while the FP-QCL emits at high currents, the FP-QCL was operated in pulsed mode with varying diode temperatures and applied currents. The spectral outputs in pulsed mode were temporally resolved using a step scan FTIR spectrometer. FP mode peaks typically broaden by driving higher currents. FP mode hopping, emerging, and disappearing were observed during the laser pulse length (3000 ns) at different applied current values. The ideal spectral characteristics for a single snap shot application are discussed, with respect to a broad spectral bandwidth, a flat-top power profile, and high spectral power density.