There are two ways to go about it.
One way would be add an extra choice on the lines of "Did not answer", and set that as the default choice. So that when you a force a response, that choice is selected and the page advances. Additionally, you can add the JS code below, to ensure that your participants don't see that choice:
Qualtrics.SurveyEngine.addOnload(function()
{
    last_choice = this.getChoices().length;
    qid = this.questionId;
    document.querySelector("#"+qid+"-"+last_choice+"-label").hide();
});

The other option would be to skip forced validation all together and just use JS to keep track of the time and click the next button when its over.

Thanks for your reply. Actually, I do want participants to answer all questions, so I have to use Force response. My main issue is that I don't want them to wait for another 300 minutes due to clicking the "next" botton when they just miss one or two questions, which happens because the timer will restart when they miss some questions and click the next botton.
I have actually finished collecting data. What I did to eliminate the issue as much as possible was adding a sentence at the end of the page to remind them to check that they have answered all the questions (in order to successfully advance to the next page).

Okay. In that case from next time you could use "Request Response" instead of "Force Response". If they miss a question and click Next, then they'll get a pop-up about it. If the time is up, the page will automatically move forward, irrespective of whether they have answered or not.

Wow, that is exactlly what I want! Thanks so much ahmedA! I will definetely try Request Response next time!