No brakes!

Brake pedal to the floor is caused by low brake fluid. Add fluid and pump the pedal. If it continues to go to the floor the fluid is leaking out somewhere. Do not drive it in this condition. After adding fluid you may need to bleed the brakes. The BAS/ESP light indicates a problem with the brake assist and electronic stability systems. Have the trouble codes read, it will give you more specific faults. Restoring the fluid levels should alleviate the warning lights, unless there is a faulty component - such as a bad master cylinder/power booster. BAS/ESP other known culprits in a Benz are the steering angle sensor as well as the stop light switch, especially if you've recently had a weak or dead battery issue. You can reset the steering angle sensor, and the stop light switch is a cheap part to replace. I'd start with getting the fluid level restored and the trouble codes scanned though.