Help, please help!124 center vent lead to stalling
 

I went to temporarily get my center air conditioning vent to open on my 1987 300E, because I was so warm with the summer heat starting here in Tn. Unfortunately, the flap was so hardened, it fell off and dropped into the bottom of the heater box! My car started to sputter then stalled. The o2 sensor and antilock brake lights came on. I cranked it. I started it,then it stalled repeatedly until my battery ran down! HELP! Thank you. :)