1991 BMW 525i Automatic

my car has beed sitting up for almost 2 years now, the key is in the trunk in a bag i used for gym back then, its been locked in there since ... the car has been sitting also cause its been running hot, so my question is , how do i get in the trunck without my key, you know it pushes in with the buttun, jus wanna know how cani get in from the back, withouth rippiing my classic apart, concerned