To say “without stopping” it’s just sem - without- plus the verb (almost any verb) in it’s infinitive form. You can use this format to say things like, sem falar, sem pagar, sem pensar, sem perguntar and so on. Very useful.
sem falar = without saying
sem pagar = without paying
sem pensar = without thinking
sem perguntar = without asking
We don't really say with looking, with saying, etc. Why not? It just sounds wrong. We say, without looking, without saying, and so on. All_the_time.
And so do Brazilians.
Without in Portuguese: useful examples
*I'm not talking about saying, without in the simpler usage like, Ela está sem roupa. (She's naked).
Can you say, without in Portuguese with other verbs in-between?
Just as we would say something like, You can go to the show with having to wear formal attire, you can do that in Portuguese. In this case, both verbs stay in the infinite tense.
If you wanted to say this using ter que it would be: Ele pode andar sem ter que parar?