Visiting Mexico for 1 day on H4 visa when H1B approved

I am from India and on H4 visa valid till 2017 and my COS is approved and H1B is valid from Oct 1st 2016 onwards. I am planning to visit Mexico and will be back to US same day.I dont want to work from october 1 , so going to mexico to get new I94 on H4.

Is this safe? Will there be any problem to get new I94 with H4 on it ?