I want to ask if I have troops wounded at coalition base, and I quit from my allies, will my troops..

Wounded troops will stay in the coalition base. If you quit your alliance then your buildings will be recalled, I believe that this will mean you cannot heal them. If you join another alliance during the event then you can place the buildings again.

At the end of the RoC event any troops in the coalition buildings will be returned to you for free so you can just wait it out if you don't need them.