I would open the clip (track 3) in WavePad, save it as ‘Track3.edit’ (keep the original file intact just in case) and perform the volume adjustments by selecting the desired portion and using the Amplify tool.
Save the file, and then load it into MixPad.
Mute or remove the original ‘faulty’ track 3 from your project. Good luck and report back if you want or need to.