They had slaughtered Ratchet, and were smelting him... Optimus and the rest of the audobots were pissed as fuck. So they all planned to go to the place and cause some damage. But the extra thing was, they were not aware that they had also captured you. As you were thought to be already dead you were fighting with all of the strength you had left (which wasn't much) to keep the humans from shutting you down, but once you heard the other bots crashing through, you knew you just had to be loud