Look on the right hand side of your centrifuge where the door latch is located. You should see a small access hole in which you can insert a heavy duty paper clip or small screwdriver tip. Insert the paperclip or screwdriver and push straight in which will move the latch locking mechanism out of the way and at the same time pull back on the door latch release. You should now be able to access your samples. Did your facility lose power or did the centrifuge just trip the circuit breaker?
Huan, Make sure that the wall circuit breaker has not tripped, too. If it has, turn the power switch on the centrifuge off first and then turn the wall breaker on followed by the centrifuge's breaker. If it still trips out get back to me.