In the DEVIS tracking experiment that is being performed at the Institute of Theoretical and Experimental Physics (ITEP, Moscow, Russia) and which is devoted to searches for 136Xe double-beta decay, the 222Rn concentration is measured in xenon samples with different content of the isotope 136Xe. The number of probable double-electron events from 214Bi decay mimicking the double-beta decay of 136Xe is estimated.