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We consider a robot-safety device system attended by two different repairmen. The twin-system is characterized by the natural feature of cold standby and an admissible risky state. Apart from tangible results obtained in the previous Literature, we introduce a Markov time called the recovery time of the system. In order to obtain the corresponding distribution, we employ a stochastic process endowed with time dependent state probabilities related to the point availability of a renewable robot without safety device. Finally, as an example, we consider the case of Weibull repair (for the robot) and deterministic repair (for the safety device). We provide several computer-plotted graphs obtained by advanced numerical methods.