MOU is generally a seperate document signed by ALPA, FAA, and company. It is not in the contract, because it is an agreement with the FAA as well.

Don't take my word for it; look it up. Ask for a copy of the MOU from a status rep. See if there is anything in it that prevents the company from taking action against a pilot that is participating in ASAP. There isn't. The MOU protects the pilot's certificate from action by the FAA, and ensures the confidentiality of the information in the ASAP program, but if the company finds out about an incident outside ASAP the MOU does not prevent them from doing anything with it.

Don't take my word for it. Maybe I am lying and the MEC is telling the truth. Read it yourself.