Pass-over in wireless sensor network routing occurs when a query agent passes over an event agent without discovering each other. Even if the two agents eventually meet, the number of hop count may add up as a result of that. In this paper we examine the pass-over problem extensively through numerical analysis and simulations. Numerical analyses (and simulation results) reveal that probability of pass-over in the context of rumor routing can be as high as 97.5% (and 92%). The outcomes indicate the seriousness of pass-over and should not be overlooked. Technique is proposed to resolve the issue. By integrating the proposed technique into rumor routing, pass-over occurrences can be eliminated completely according to our simulations, which then results in higher routing success rate and shorter routing paths.