I currently work on a med/surg floor. Are your techs the same thing as CNAs? At my hospital, techs/CNAs are pretty synonymous, but then we have actual techs on our Obs floor and in the ED who can do more things like IVs and blood draws.
I know from personal experience, I have gotten way more experience working med/surg! Now ideally I would love to work full time in the ICU lol. So if that's what you want then go for it! There's a pretty big difference between working full time and PRN, though, so I'm not sure how that will affect your decision.
I do have to say, however, that the CNAs in my hospital in the ICU don't do a whole lot...being that the nurse to patient ratio is usually 1:2 (on med/surg here it's 1:5 so the nurses need more help), the nurses like to do everything themselves. Including emptying foleys, repositioning, and even ADL charting. I've worked in the ICU a lot and while there is a lot going on down there, I get way more hands on experience working med/surg. In the ICU all I ever do is blood sugars, set up rooms, and the occasional bedpan.