This one sounds like you might have a belt driven accessory going bad, freezing up, when engaged it causes extreme load on the engine, and when not the engine runs fine, the loud screech you heard gives you a hint that it is likely a belt driven unit grabbing, I would check the compressor first, totally shutting down the A/C, see if it does it again if it does, then check the other units. That is where I would start, Good luck!
Regards,
Brian