Look in the hl2 folder. SourceMods have a search path. They first check the mod's folder (Ie, "tf", "cstrike"), then fall into the default hl2 folder. The HL2 folders also have a modevents.res, and its loaded as well.
If TF2's modevents.res doesn't have player_hurt, then it's coming from the hl2 copy of modevents.res