No need to get hotel near lab. It's only working on weekends. There is Taxi stop just in front of berghain.
No lockers. No rooms. Few cabins. Lab is a club. Not bath house or porn cinema. There are few slings around the club. Few areas with mostly sex action. But there is also area where you can just talk, sit or walk around. It's lab.oratory.
Once you pay entrance you get card number and plastic bag to put your stuff in. Then you get it to guys at wardrobe. They write the number usually on your shoulder.
Keep you key card Safe as you should not carry with you anything of value or cash. You get drinks just by showing your number. When you are ready to leave, get your stuff and dress up, with number card pay your drinks at bar, keep receipt as you need it to get out of the club.
I always keep stuff i need in my football socks. Like card number, lube, xems, condoms (?) or whatever you need. Better not carrying any of value. All is safely stored in wardrobe.
There is shower area if you need it.