A device and a method of temporarily increasing power of at least a first turbine engine is disclosed. The device includes a coolant liquid tank and a first injection circuit connected to the tank and leading to at least one injection nozzle suitable for being installed upstream from at least one compressor stage of the first turbine engine. This first injection circuit includes at least a first flow valve configured to open when a pressure exceeds a predetermined threshold compared with a downstream pressure from at least one compressor stage of a second turbine engine so as to enable the coolant liquid to flow towards the injection nozzle of the first injection circuit.