Zombie walkers

Well i have a question, but better safe then sorry, in my 55 gallon i have 4 Nassarius Snails and i plan to add 4 more after my sand bed cleaning and water change, but question is, i can never see them, since they bury themselves under the sand (which is cool to watch them come out, nickname zombie walkers) but since i can't see them, im afraid to siphon my sand bed, i don't wanna suck one up in the siphon tubing? If i do or at least i catch him before he gets sucked up, i won't kill them doing this will i? Any ways to avoid this issue?