Used to be that most Verizon smartphones had an option to either show the incoming call or send it straight to voice mail.
Otherwise, yes, the data will pause while the incoming call shows up. If you Decline the call, then the data should pick right up from where it left off.
It should be pretty quick and seamless. The data connection itself only pauses. It doesn't drop unless you take the voice call. (And even then, it's supposed to take less than six seconds to renew a data connection after a voice call ends, but I've seen longer.)