Biological processes such as wound healing and cancer cell invasion rely on the collective and coordinated motion of living cells. A little understood aspect that influences these processes is the pressure differences within and between different parts of the body. Researchers designed model tumor systems using cervical cancer cells in collagen matrices to investigate whether pressure differences can push cancer cells into their surroundings. Upon embedding the model tumors into a soft matrix, an increased pressure led to a sudden burst of rapid and coordinated cellular motion that sprayed outwards from the tumor.