  We use the short-time inference scheme (Manikandan, Gupta and Krishnamurthy,
Phys. Rev. Lett. 124, 120603, 2020), obtained within the framework of
stochastic thermodynamics, to infer a lower-bound to entropy generation rate
from flickering data generated by Interference Reflection Microscopy of HeLA
cells. We can clearly distinguish active cell membranes from their ATP depleted
selves and even spatio-temporally resolve activity down to the scale of about
one $\mu$m. Our estimate of activity is model--independent.
